# The Kart Engine Thread



## cpr (Jan 1, 2011)

Feel free to share your knowledge of the McCulloch, West Bend, Power Products, and Homelite engines here. Please try to keep it to the kart engines, tech, resources, tricks, etc.

I'll start off with a question. I have several MC-10 based 87cc McCullochs. While I have never been able to verify that the blocks are different, meaning port timing and sizes, the heads are different on the saws. The saws have the spark plug opposite the exhaust port. With 2-stroke motors, the theoretical advantage of placing the plug opposite the exhaust port for maximum mixture combustion before port opening is intuitive, I have to wonder what other differences there are. Is the central plug MC-10 head more conducive to power with flame front propogation in all directions around the head and across the piston? Is the combustion chamber smaller on the kart head than the saw head? I know hood clearance would be necessary to acommodate the plug like on a D-44, but could I pick up some saw performance with a head swap?


----------



## Brian13 (Jan 1, 2011)

Subscribing . Do you know if the Mc-10 has a thinner head gasket then the S44A does?


----------



## cpr (Jan 1, 2011)

Don't know Brian. I have seen various thickness head gaskets, though.


----------



## Jacob J. (Jan 1, 2011)

First off- the kart blocks do in fact have different port timing than the saw blocks, by and large. The kart motors were designed to make their power at a higher RPM, and the saw motors were made to peak much lower. This was as much to do with cutting attachments of the day than anything. It wasn't advantageous to design saws running hardnose bars and 1/2" or 9/16" pitch (mostly semi-chisel or chipper) chain and try to get them making peak power at 9k in a 87-103cc motor. 

Yes, for the most part the kart heads have a smaller CC than the saw heads. There is a performance gain from swapping heads but you have to make sure you have the head with the correct bolt spacing. Also, I can't remember for sure, but I think the larger, square kart heads wouldn't fit under some of the saw shrouds without modification.

Some of the kart guys are converting the saw engines over to replica kart motors. It takes a lot of work in changing port timing, (in some cases) ignition timing, external parts, and utilizing the kart intakes and exhausts. 

I sure wish there was more of a secondary market on the aftermarket stuff for the West Bends and Power Products motors. I had to wade through a ton of crap to find a Wiseco thin-ring West Bend 820 piston. It only took about 12 years. umpkin2:


----------



## Busmech (Jan 1, 2011)

*Kart pistons*

I guess I was lucky I got a wiseco thin ring 820 piston off ebay last year after about eight years search. I have several mac 101 pistons, all from ebay, rods are the thing I am having a problem finding.


----------



## cpr (Jan 1, 2011)

Figured this would draw you out JJ. You've probably got as much exprience as anyone here with these, thanks again and in advance for sharing your thoughts.

Let's develop the theory a little more. Does higher rpm automatically mean more hp? In the abstract, it might, but as you note, this may not translate to a faster cut. Thrown into 30" plus of hardwood hauling some FAT chain, the saw blocks may enjoy a torque advantage that going to a kart block may not soon surpass.

MC-10 heads seem to be "affordable" vs entire engines. May have to do some experimentation in the future.


----------



## Jacob J. (Jan 1, 2011)

No, higher RPM doesn't translate necessarily into higher HP automatically. I actually prefer in many cases, the saw blocks, especially in larger displacement. My latest project involves cutting the heads off of three SP-125 blocks, having them bored out .050" over and chromed, and then fitting custom heads to them. Two will get all-new manufactured heads while the third will get a custom WB-820 head that has larger cooling fins. 

One of the biggest complaints I heard from guys (including my dad and grandpa) who ran the kartsaws in the woods was the high temps they ran at. After I tore down all my dad's saws I could easily see what he was referring to. There was a lot of really baked-on stuff that had seen high temps.

Hopefully we can get Lee involved in this thread as well, since he's built up some of the kartsaws. Jay (Bigbore577) and Hoss both have 101b kartsaw rigs. 

Another of my kooky ideas involves a Homelite 990 saw chassis, an Mc-7 crank, an Mc-90 .010" over domed piston (thin rings), an Mc-93 rod, and a Mikuni 34mm carb. It's a witches' brew but might make a good runner.


----------



## Jacob J. (Jan 1, 2011)

Another good thing about those early saw blocks like the D-44/55 is that they have the steel sleeves, so there's flexibility there in adapting them to handle a particular load range. Some of the kart blocks don't give you that option.


----------



## heimannm (Jan 1, 2011)

I'll watch, and hopefully learn something here.

Mark


----------



## ttyR2 (Jan 2, 2011)

Though y'all might like to see some pictures from early '60's Hot Rod magazines specific to karting. Some McCulloch action:

Mac 55's:











Mac 99:





Triple Mac's:





Dual MC-6's:


----------



## crmyers (Jan 2, 2011)

Great pics, this thread is looking better and better.


----------



## Bill G (Jan 2, 2011)

Here is a Mercury-Disston KB7 on a kart.


----------



## blsnelling (Jan 2, 2011)

Very cool info. I know little to nothing about these engines, but I find them intriguing.


----------



## nmurph (Jan 2, 2011)

Bill, get that pic up. that is a combo i have not heard of for a cart motor.


----------



## Bill G (Jan 2, 2011)

I am trying to figure out the pictures now that all changes have been made. I will try again as an attachment. Someone please post it directly if I get it attached.

Bill


----------



## blsnelling (Jan 2, 2011)

Here ya go Bill.


----------



## Bill G (Jan 2, 2011)

Now how did you get the pic to show up


----------



## blsnelling (Jan 2, 2011)

Bill G said:


> Now how did you get the pic to show up


 
Do a quote of my post and you can see the HTML. All you have to do is copy the URL of the pic, then click the image icon just above the message body you're typing, and then paste it in.


----------



## Bill G (Jan 2, 2011)

I can understand that simply enough because the pic was hosted here once I posted it as attachment. What I need to figure out is how to do it from a pic saved on my camera.

Bill


----------



## Bill G (Jan 2, 2011)

Here is a Disston DA 211 with AH 58 cylinders and pistons


----------



## cpr (Jan 2, 2011)

Great stuff guys, keep it coming! This is what I had in mind.


----------



## Bill G (Jan 2, 2011)

Here I will try the pics again


----------



## Tzed250 (Jan 2, 2011)

Bill, that engine is beautiful!


.


----------



## Bill G (Jan 2, 2011)

Tzed250 said:


> Bill, that engine is beautiful!
> 
> 
> .



Both the KB7 and the DA211 engines belong to couple longtime kart racers on the west coast. A few years ago I sold them some spare Mercury-Disston engines I had. I wish I had the talent to do what they did .

Bill


----------



## Jacob J. (Jan 2, 2011)

Tzed250 said:


> Bill, that engine is beautiful!
> 
> 
> .


 
I believe that's the engine that Will Rogers built, but Jack Canady was the first to build one of those years ago. Both are long time kart guys and good machinists/mechanics Jack has been experimenting with hybrid kart engines for a long, long time.


----------



## Bill G (Jan 2, 2011)

JJ,

Will and Louie


----------



## Jacob J. (Jan 2, 2011)

Bill G said:


> JJ,
> 
> Will and Louie


 
Oh gotcha. I talked to Jack years ago about building one of these, around '98 and '99. I traded him some PP parts at that time. I had two running, mounted 58 engines converted from an Air compressor and a water pump.


----------



## wigglesworth (Jan 2, 2011)

Jacob J. said:


> two running, mounted 58 engines...


 
I got one of them.  Well, it fires on a prime. I havent done anything else with it.


----------



## rwoods (Jan 2, 2011)

Jacob J. said:


> No, higher RPM doesn't translate necessarily into higher HP automatically. I actually prefer in many cases, the saw blocks, especially in larger displacement. My latest project involves cutting the heads off of three SP-125 blocks, having them bored out .050" over and chromed, and then fitting custom heads to them. Two will get all-new manufactured heads while the third will get a custom WB-820 head that has larger cooling fins.
> 
> One of the biggest complaints I heard from guys (including my dad and grandpa) who ran the kartsaws in the woods was the high temps they ran at. After I tore down all my dad's saws I could easily see what he was referring to. There was a lot of really baked-on stuff that had seen high temps.
> 
> ...


 
I assume the elder Js ran kartsaws because they cut faster. If so, is this due to more overall power or a change in the power curve to higher rpms? Just how many rpms does a logging MAC kartsaw turn? Ron


----------



## sawbones (Jan 2, 2011)

some homey stuff


----------



## cpr (Jan 2, 2011)

Holy smokes, the John Deere G flywheel of the 2 stroke world...


----------



## Brian13 (Jan 2, 2011)

I had read in a older thread, that in order to take full advantage of a kart engine it would require heavy modification to the intake. How does a kart engine effect the saw with a standard saw intake and carb. I have been wanting to build another Super 250, but with a Mc-92 in it but not a hot saw. Using that for example, running a Super 250, and one with the kart engine with standard saw intake, what differences can you expect? Higher RPMs with a little less torque, all around more torque and RPMs, or something else? I know its kind of hard to quantify, but learning how the porting effects the performance is of interest to me.


----------



## Jacob J. (Jan 2, 2011)

rwoods said:


> I assume the elder Js ran kartsaws because they cut faster. If so, is this due to more overall power or a change in the power curve to higher rpms? Just how many rpms does a logging MAC kartsaw turn? Ron


 
Change in the power curve for sure. The kart engines do make more overall power in any configuration. It does help to use different intakes, carburetion, exhausts (in some cases.) If you're going to run a kart in a saw though, you'd want to find one with stock or almost stock ports. A lot of kart engines have had the exhaust port molested and that really hurts the torque levels of the engine.


----------



## ttyR2 (Jan 2, 2011)

I remember reading this book that I borrowed from the library over and over and over again. Had a lot of info about modifications (circa 1961).

Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & more


----------



## Jacob J. (Jan 2, 2011)

Brian13 said:


> I had read in a older thread, that in order to take full advantage of a kart engine it would require heavy modification to the intake. How does a kart engine effect the saw with a standard saw intake and carb. I have been wanting to build another Super 250, but with a Mc-92 in it but not a hot saw. Using that for example, running a Super 250, and one with the kart engine with standard saw intake, what differences can you expect? Higher RPMs with a little less torque, all around more torque and RPMs, or something else? I know its kind of hard to quantify, but learning how the porting effects the performance is of interest to me.


 
What you'll get is an engine that makes its power at a different RPM range. Yes, opening up intake and using a custom reed cage, manifold, and larger carb gets you more power but that's true on any 2-cycle engine. Higher RPM, more overall power, but it's a different torque band. You get a lot more heat with the higher compression of the kart motor as well.


----------



## cpr (Jan 2, 2011)

Seems most, if not all, of the 101 powered saws I have seen include a decomp valve that was never a part of the original engine. Was a head swap performed, or were they added as part of the dealer-installed option? Is there a boss cast in where one can be placed?


----------



## Jacob J. (Jan 2, 2011)

You have to grind a spot in the head for a de-comp. There's not really a boss per se', but a cast area in the head that has more material where one can be installed. I've drop-started ones without it and it's miserable. Even with one installed with the timing stock can rip the handle right out of your fingers. It's no wonder a lot of the old-timers have carpal tunnel problems.


----------



## cpr (Jan 2, 2011)

I hear that. Never even bothered to try drop starting ANY of my Macs, especially after one of them caught, ripped the handle from my right hand and bloodied my left thumb on it's way back to the housing at 200mph...


----------



## Busmech (Jan 2, 2011)

I have 4 broken d handles from starting my 101AA hot saw (no decomp).


----------



## Saw Dr. (Jan 2, 2011)

ttyR2 said:


>


 
That is the first one of those engines I have ever seen that NEEDED the airbox lid turned backwards. The Ebay clowns are all trying to get ram-air on their saws, and the cart racers forgot to.....

Hey, that reminds me: Anyone know the maximum RPM of the hundred and first kartsaw points electronic racing MAC????

:angry2::angry2::angry2:


----------



## cpr (Jan 27, 2011)

The FrankenMess is mine to own. Seller and feebay broke it off in me so I'm walkin' funny...

Gathering info for what it's going to become. Not a full on kart-saw, but it will incorporate kart principles during the build for a factory hot-rod saw: I christen it the FX-125.

JJ made an absolutely brilliant post here:http://http://www.arboristsite.com/chainsaw/135464-3.htm#post2213056

Since the FrankenMess seems to have a CP-125 block, JJ mentions the concept of intake timing. I thoroughly understand the idea of intake timing on a piston ported engine, but on a reed ported engine my understanding is lacking (we'll exclude from our discussion transfer timing).

How is intake timing determined on a reed ported engine?


Lot's going on here in my personal and professional life, but as time permits, look for a brand new thread on the FX-125 build. It's going to be a blast, but have patience with me, please :handshake:.


----------



## Eccentric (Jan 27, 2011)

cpr said:


> The FrankenMess is mine to own. Seller and feebay broke it off in me so I'm walkin' funny...
> 
> Gathering info for what it's going to become. Not a full on kart-saw, but it will incorporate kart principles during the build for a factory hot-rod saw: I christen it the FX-125.
> 
> ...


 
Glad to see you finding the silver lining in the whole "working Chris 'til he can't take it no more" fiasco. At least you still have the "Franken-Kart Saw" thingee. You *could* have ended up out of pocket *and* without the saw at the end of the deal. 

We'll be patient with you........................................now go get busy with this build dammit!!!


----------



## cpr (Jan 27, 2011)

Right on, friend!!! Gotta get the high side flowin' on the Super 250, the low side flowin' on the Super 44, the ignition goin' on the D44... In the meantime, I'll start teardown of the Mess and get a list going... Have no fear.

The deal hurts, but... Well, see my sig for the words of guidance.


----------



## GASoline71 (Jan 27, 2011)

Great thread! 

I've learned that the Super 250 and the Mc49 are round about the same. Prolly port timing differences. Kewl...

Gary


----------



## PLMCRZY (Jan 27, 2011)

My Dad use to race one in the late 60s early 70s. He told me it had a MAC engine, it would get his sisters gto off the line then around 60mph she would fly right past him. He stopped racing after his buddy wrecked and broke his neck one race. I was always curious to what it looked like, he said you practically laid down in it. Engine was right by your head.


----------



## nmurph (Jan 27, 2011)

Saw Dr. said:


> Hey, that reminds me: Anyone know the maximum RPM of the hundred and first kartsaw points electronic racing MAC????
> 
> :angry2::angry2::angry2:


 
hey, you trying to hid from someone??? maybe someone in a farun country????


----------



## cpr (Feb 6, 2011)

Watching the Super Bowl and contemplating saw surgery...

Anyone care to enlighten me on stuffer plates?

I'd like a better understanding of:

1. How do they work?

2. Why are the long-tail GEM ones better?

3. If you drill the oiler hole in a GEM stuffer, will it work in a CP/SP 125?


----------



## leeha (Feb 6, 2011)

The purpose of the stuffer is the eliminate crankcase air volume.
This is so when the piston is on it's down stroke there is less air
to compress so the whole charge will pass into the ports and cylinder.
Aftermarket stuffers fill more of the case over a stock stuffer.
This help to get the most of the fuel charge to the top of the piston.



Lee


----------



## thomas72 (Feb 6, 2011)

I have seen larger stuffers to reduce crank case volume along with epoxying all the threaded holes, and putting in a full circle crank. Every little bit helps.


----------



## cpr (Feb 6, 2011)

Interesting. I'd always taken the full-circle cranks as being important for torque (flywheel effect) and vibration damping, less for volume filling.


----------



## heimannm (Feb 6, 2011)

Don't drill a hole in it, you'll lose the benefit of the volume filling characteristics.

Mark


----------



## cpr (Feb 6, 2011)

heimannm said:


> Don't drill a hole in it, you'll lose the benefit of the volume filling characteristics.
> 
> Mark


 
HAHA! Yeah, but if it runs like I hope it will when I'm done, the power trade-off won't be worth the nuked vintage bar!


----------



## thomas72 (Feb 6, 2011)

I have also seen on dirt bike cranks where little ridges are ground like small fan fins around the circle part of the crank in an effort to get the air and fuel mixture into the ports faster. I do not know if this actually worked, but people pay a good bit of money to have it done. Also, if you cut down Boyesen reed valves and put them in a saw would probably help. They seal better than stock reed valves and will also let more fuel/air travel past them. Another little trick on bridge ported engines is to drill small holes in the piston skirt that line up with the bridge port. This helps keep the piston from galling there and beating out the port.


----------



## Brian13 (Feb 16, 2011)

Been watching this video cpr posted awhile ago, and it has me thinking. With my S44A being based off the MC10 I was researching the stroker kit. Not a whole lot of info, and havnt seen any for sale. If I am understanding this video right, instead of using a stroker kit, he just went to the next size crank, and got a thicker head gasket as well as a spacer for the stuffer. Am I understanding this right? Is it feasible to take a MC20 crank and use that with a thick head gasket on the S44A with the stock rod and piston? About 6min into the video is where he starts to talk about it.

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/R2ZGg0LYSRI" frameborder="0" allowfullscreen></iframe>


----------



## heimannm (Feb 16, 2011)

Interesting stuff indeed.

I found a more or less complete Mc40 last week, and have a good line on a couple of Mc10's. No 101's yet but it is a start.

I added the carburetor and engine mount from my big box (officially crazy thread) just to dress it up a bit and make it possible to hold it in my mounting device.

Now I need to find a new set of rings (47767), or maybe more than one set to be ready for the future.

















Mark


----------



## Brian13 (Feb 16, 2011)

What are you going to do with that Mc40? I have given up on the 101s for now, too expensive. Wouldnt mind a decently priced Mc10 though to go into the S44A.


----------



## cpr (Feb 16, 2011)

Looks promising Mark. Randy says go 6ci and fear no evil. To paraphrase, go kart or go home.


----------



## heimannm (Feb 16, 2011)

Seems to me the Mc40 or Mc10 could easily slip in to a Super 44 or 1-70 frame and make a very interesting under 5 In³ vintage saw.

Hey, I may have one or two of those old saws up on a shelf, something to think about...

Mark


----------



## cpr (Feb 16, 2011)

Me, too. With JJ's encouragement, I mean to try putting an MC-10 head on a saw block. Torque and HP combo. I reckon a Super 44A will cross paths with the heads I scored soon enough.


----------



## cpr (Feb 18, 2011)

Actually, I would rather have hamburger b...


























Plenty to keep me busy and there's another arriving soon...


----------



## Teddy.Scout (Feb 19, 2011)

THIS THREAD IS OVER DUE!!!!!!!!!!!!!!!!!!!!!!!!
Hats off CPR!! (all good reading!!)


----------



## heimannm (Feb 19, 2011)

I made a few phone calls this week and managed to get to see the pair of Mc 10's, a few more phone calls and they came home with me.

The Mc 10 has a 2.125" bore like a lot of saws, and uses the same 55123 rings (thick rings) as many of the 80 and 87 cc saws. It is interesting as it has the "external" breaker points like the D-44 and 1-70 family saws.

Dusty from setting on the shelf for a while, but I think they will clean up nicely. Pistons both look good through the exhaust side, could be some fun.






















Mark


----------



## Brian13 (Feb 19, 2011)

Real nice find!!! You gonna put those in a saw?


----------



## cpr (Feb 19, 2011)

Way to go Mark! When you get a chance, could you post a pic of the stuffer plate on those from the external side, not the inside. Also, are the cranks machined for keyways on the taper or no?


----------



## Eccentric (Feb 19, 2011)

heimannm said:


> I made a few phone calls this week and managed to get to see the pair of Mc 10's, a few more phone calls and they came home with me.
> 
> The Mc 10 has a 2.125" bore like a lot of saws, and uses the same 55123 rings (thick rings) as many of the 80 and 87 cc saws. It is interesting as it has the "external" breaker points like the D-44 and 1-70 family saws.
> 
> ...



Nice scores Mark! Do spy a certain McCulloch 77 hiding under a rag in a few of those pics? Can't keep 120cc of McCulloch gear drive muscle under wraps for too long...


----------



## heimannm (Feb 19, 2011)

That is a 77 hiding under the terry towels Aaron. What was the red sealer you used?

Charles, I will pull the sprockets and see what lurks underneath. I think they are tapered with a key way, the PTO end of the Mc 40 is definitely tapered with a key way (and badly worn). The IPL definitely shows a tapered shaft with a key way.

I will have to dismount one and get a photo from the end.

Brian, I hope to get one of the Mc 10's running and into a D-44 or 1-70 chassis. Next step will be to find one of the handy guys and see about building a pipe for it.

Mark


----------



## cpr (Feb 19, 2011)

Thanks, Mark. Curious what you find. I have a service bulletin stating the importance of the key and keeper nut in retaining the clutch, yet this 101b I have has no scallop for a key in it. It was built for a fluid clutch in a kart, so that may play a factor. So much to learn... Not sure at this point if I should seek to have one machined into the crank or not worry about it.


----------



## Brian13 (Feb 19, 2011)

heimannm said:


> Brian, I hope to get one of the Mc 10's running and into a D-44 or 1-70 chassis. Next step will be to find one of the handy guys and see about building a pipe for it.
> 
> Mark


 
Looking forward to seeing that!!! I have half an eye open for a Mc10, if I find one before I find the piston I might throw that in the S44a. Cant wait to see what you come up with!!


----------



## shawn022 (Feb 19, 2011)

First off, I don't know anything about Macs let alone kart engines but I was talking to my neighbor awhile back about racing. He and some other neighbors used to be pretty heavy into karting back in the day. He said they ran 101 A's and 101 B's. So i guess my question is whats the differance between the A's and the B's? Thanks


----------



## cpr (Feb 19, 2011)

Not well versed in the variations. There was A, AA, B, C, D, and M.


----------



## rwoods (Feb 19, 2011)

shawn022 said:


> First off, I don't know anything about Macs let alone kart engines but I was talking to my neighbor awhile back about racing. He and some other neighbors used to be pretty heavy into karting back in the day. He said they ran 101 A's and 101 B's. So i guess my question is whats the differance between the A's and the B's? Thanks


 
Try McCulloch Kart Engines ..................... ron


----------



## Eccentric (Feb 19, 2011)

heimannm said:


> That is a 77 hiding under the terry towels Aaron. What was the red sealer you used?
> 
> Charles, I will pull the sprockets and see what lurks underneath. I think they are tapered with a key way, the PTO end of the Mc 40 is definitely tapered with a key way (and badly worn). The IPL definitely shows a tapered shaft with a key way.
> 
> ...


 
I used the Permatex Hi-Tack stuff that comes in the can with the brush built into the lid. Lee H recomended it. That stuff never really hardens completely. Sort of like rubber cement when it dries. You should be able to get it off pretty easily. Sorry I made a bit of a mess of it. Was in too much of a hurry when I buttoned it back up. 

Did you get that NOS carb metering diaphragm that I sent you the link for? The seller was somebody who frequents another saw forum. Somebody got it..........or the listing just ran out and they still have it for sale. I'll PM you their info if you still need one. For all I know, you have a stack of the dang things already...


----------



## cpr (Feb 19, 2011)

rwoods said:


> Try McCulloch Kart Engines ..................... ron


 
Excellent resource, but beyond the "c" block having a bridged exhaust and a couple of other things, I could't find a difference that wouldn't bolt onto any other 101 block (ie the air horn flywheel shroud).


----------



## shawn022 (Feb 19, 2011)

Wow, lots of info there.


----------



## Busmech (Feb 20, 2011)

cpr said:


> Thanks, Mark. Curious what you find. I have a service bulletin stating the importance of the key and keeper nut in retaining the clutch, yet this 101b I have has no scallop for a key in it. It was built for a fluid clutch in a kart, so that may play a factor. So much to learn... Not sure at this point if I should seek to have one machined into the crank or not worry about it.


 
I currently have five running 101's, various models, all in saw frames none of which run a key. Some have the keyway some don't, just make sure the taper is clean and smooth and get them as tight as possible, i use an 18inch breaker bar.


----------



## heimannm (Feb 21, 2011)

CPR, see the photo for the Mc 10 stuffer from outside. Notice there is even the hole for the manual oiler on a saw.

This block was originally stamped 1-70 over 1-80, both X'd out and the Mc 10 stamp on the boss where the lubrimac oiler would have been.

Both have a keyed and tapered shaft but it appears to me to be longer than a saw crank shaft would be from just looking at it. Maybe tonight I will find a clutch to put on there and see how it looks.






Mark


----------



## Brian13 (Feb 21, 2011)

There seems to be two different lengths for the kart cranks. Its the ignition side that varies. Not sure witch the MC10 falls into though. The super series has the shorter crank. McCullock Kart's and comments from Steve O'Hara, ,,,,,,,


----------



## cpr (Feb 21, 2011)

Thank you Mark. Crank looks about right for length.


I wanted to see what that stuffer looked like. That one could be drilled for an auto oiler and used in a saw. The one on my 101 won't work because the oiler tank won't mate to it due to the gusseting cast into it. Look at the pics above to see what I mean.


----------



## RandyMac (Feb 21, 2011)

Gosh, that sounds like work.

This looks like a bolt on.


----------



## RTK (Feb 21, 2011)

This has inspired me to pull out my old mac 92 kart engine.


----------



## cpr (Feb 21, 2011)

Another question for you Mark. What carbs are on those MC10s? Look like flatbacks of one sort or another, but the pump housing isn't flat. Never seen those before.

Lord, carbs for these engines could occupy a thread in itself!


----------



## heimannm (Feb 21, 2011)

The carburetors on the Mc 10's are the small McCulloch kart carburetor. The use the flat back fuel pump and metering diaphragms. I think the three that I have (including the one on the Mc 40) are all the venturi style and not the pressure pulse type but I haven't actually been inside them yet.

Mark


----------



## Rounder (Feb 21, 2011)

RandyMac said:


> Gosh, that sounds like work.
> 
> This looks like a bolt on.
> 
> ...


----------



## cpr (Mar 15, 2011)

I had a nice talk yesterday with a gentleman that had a top end for my AH-81.

He told me about the Frankenstein stuff they used to do with the 81 motors. The wildest he got was to cut the top of the jug off to fit a sleeve that could accept a US-820 piston and then put a head on it. He said it wasn't a high-winder, but the torque out of corners would snap your head off.


----------



## cpr (Mar 15, 2011)

Nirvana.


----------



## stinkbait (Mar 15, 2011)

cpr said:


> Nirvana.


 
No wonder I cant have a kart engine!:jawdrop:


----------



## leeha (Mar 15, 2011)

Now thats an impressive collection of vintage
Mcculloch kart motors. Lot of dollars sittin there.




Lee


----------



## wigglesworth (Mar 15, 2011)

cpr said:


> Nirvana.


 
I told you guys to stay out of my shop....geeze.


----------



## heimannm (Mar 15, 2011)

$50 to $100 K I reckon...

Mark


----------



## RTK (Mar 15, 2011)

I'm in need of a few parts for a mac92. Do you have any parts for sale??


----------



## cpr (Mar 15, 2011)

RTK said:


> I'm in need of a few parts for a mac92. Do you have any parts for sale??


 
Wish it was so.

Those belong to a kart racer elsewhere on the net...


----------



## Brian13 (Mar 15, 2011)

Man I would love to have all that sitting around:hmm3grin2orange:.


----------



## Eccentric (Mar 15, 2011)

cpr said:


> Nirvana.


 
Holy CRAP Charles! I sat here in stunned silence for more than a few minutes............................just looking at those pics with glazed eyes...:yoyo:


----------



## cpr (Mar 15, 2011)

Eccentric said:


> Holy CRAP Charles! I sat here in stunned silence for more than a few minutes............................just looking at those pics with glazed eyes...:yoyo:


 
Yeah, I'm still mopping up the drool from when I saw these.

You should see the 8, EIGHT, MC-10s this guy built.

So touched by the excess, I had to pour myself a drink! 

Helps me cope with my 101 not being here yet.


----------



## RandyMac (Mar 15, 2011)

there is a first class perv.

crp, I'm joining you, down the hatch.


----------



## cpr (Mar 15, 2011)

How come we're standing here drinking when we should be washing?


----------



## Eccentric (Mar 15, 2011)

cpr said:


> How come we're standing here drinking when we should be washing?


 
I'll drink to that...........then off to hit the rack. Back up at 0420hrs again tomorrow.


----------



## cpr (Mar 15, 2011)

Good night

and good luck...

Kinda early for taperin' off on the west coast...

Wha', wha'? Time isn't the same everywhere?


----------



## RandyMac (Mar 15, 2011)

Eccentric said:


> I'll drink to that...........then off to hit the rack. Back up at* 0420hrs* again tomorrow.


 
bummer dude.


----------



## Eccentric (Mar 15, 2011)

cpr said:


> Good night
> 
> and good luck...
> 
> ...



Thanks Charles. You're right. it's just 7:30PM (1930) here.......But since I usualy don't hit the hay until 0100 or 0200.............getting to sleep on the 'day shift' schedule takes a LONG time. I have some serious tossin' and turnin' to look forward to. Best start early (and with some natural and brown liquer sleep aids). Will spend a bit of 'snuggle time' with the girls first too.



RandyMac said:


> bummer dude.


 
Yep. I'll be glad when I'm off this modified duty day shift ####.


----------



## cpr (Mar 15, 2011)

Right...


----------



## Brian13 (Mar 15, 2011)

:drool:


----------



## Eccentric (Mar 16, 2011)

cpr said:


> Right...


 
Nice. I dig seeing the kart engine next to my post on yer laptop. Of course, I'd *rather* see that engine on *my* computer desk with *your* post in the background...


----------



## Rounder (Mar 20, 2011)

Any progress reports?...................


----------



## cpr (Mar 20, 2011)

Stock port 101, still waiting for it to get here.

PP top end, still waiting for it to get here.

Probably won't work on any of it this week, want to be ready for the Ontario GTG.


----------



## RTK (Mar 20, 2011)

Does anyone know of a good place to find parts for these kart engines


----------



## cpr (Mar 20, 2011)

Google's a start, feebay, and "other places" have been quite friendly for me and I have yet to encounter any animosity about putting these in a saw as opposed to a kart. Guys seem to be happy that anyone is paying attention and have money to spend.


----------



## Jacob J. (Mar 20, 2011)

cpr said:


> Google's a start, feebay, and "other places" have been quite friendly for me and I have yet to encounter any animosity about putting these in a saw as opposed to a kart. Guys seem to be happy that anyone is paying attention and have money to spend.


 
That's been my experience as well. Even saw guys are well received on the karting forums and I've traded many, many parts with kart guys and helped kart guys with the conversion of saw engines for use on the karts. That's the good thing about the Macs and West Bends, there's literally millions of them around so no shortage for anyone.


----------



## Jacob J. (Mar 20, 2011)

Jacob J. said:


> That's been my experience as well. Even saw guys are well received on the karting forums and I've traded many, many parts with kart guys and helped kart guys with the conversion of saw engines for use on the karts. That's the good thing about the Macs and West Bends, there's literally millions of them around so no shortage for anyone.


 
It does bother me though when I see saws like the Solo or Echo twin-cylinders chopped up to make an R/C airplane or boat motor.


----------



## sawbones (Mar 20, 2011)

Jacob J. said:


> It does bother me though when I see saws like the Solo or Echo twin-cylinders chopped up to make an R/C airplane or boat motor.




so tell me where the echo twin parts went, I need some.


----------



## Jacob J. (Mar 20, 2011)

sawbones said:


> so tell me where the echo twin parts went, I need some.


 
They usually just throw 'em away.


----------



## asand1 (Mar 20, 2011)

stinkbait said:


> No wonder I cant have a kart engine!:jawdrop:



What a waste, why should they exist if you aint gonna use them.
Vintage Kart races waiting to happen.

I'd like to see a kart with 35hp 2cyl rude OB motor sporting a heater core radiator. Porting and polishing plus pipes added to the stock adjustable timing should be a fire breather.


----------



## cpr (Mar 24, 2011)

Inside the Power Products AH-81 jug, 130cc.

Exhaust port is at the bottom, transfers to the sides. Hemi? Eh, no. Flat head. Ports are like in a McCulloch as the rings float.






A look in through the exhaust.






Jug and goofy window ported piston, more on that below. Jug came out at 2.503, no taper I could find, piston is 2.498 on the skirt.






It seems this thing transfers through those holes in the piston skirt only. I need to pop the old jug and look at the case, because the ducts are there. If they're useable, this engine should wake right up if the case will permit.






Lastly, the port map.






The corresponding ports in the piston are .750 dia at .850 from crown to top of port.

Time to start wrenching... this weekend.


----------



## RTK (Mar 24, 2011)

Keep us posted


----------



## turtle561 (Mar 24, 2011)

*wish granted*

I'd like to see a kart with 35hp 2cyl rude OB motor sporting a heater core radiator. Porting and polishing plus pipes added to the stock adjustable timing should be a fire breather.[/QUOTE]

asand1- google rearenginekarts.com view topic the big one 2008 and click 'the hovey hawk konig at riverside-video' several amazing vids of what you described. these are restored vintage karts from the late 50's early 60's.


----------



## promac850 (Mar 24, 2011)

How bout a 'kart' called a Honda CR-X? I wanna shove an Evinrude 250 hp v8 outboard engine in that with a manual trans... 

I hope to be able to build a good kart someday with a Rotax 800 triple in it...


----------



## cpr (Mar 24, 2011)

promac610 said:


> How bout a 'kart' called a Honda CR-X? I wanna shove an Evinrude 250 hp v8 outboard engine in that with a manual trans...
> 
> I hope to be able to build a good kart someday with a Rotax 800 triple in it...


 
My personal choice for a "beyond kart" saw would be a 582 with the aero dual plug heads. Far beyond my fab skills at present, I'm afraid.


----------



## Eccentric (Mar 24, 2011)

cpr said:


> Inside the Power Products AH-81 jug, 130cc.
> 
> Exhaust port is at the bottom, transfers to the sides. Hemi? Eh, no. Flat head. Ports are like in a McCulloch as the rings float.
> 
> ...


 
Great info Charles. Neat old engines. IIRC, a McCulloch 77 chainsaw has the same bore as that AH81. Must have a shorter stroke, as that engine is "only" 7.3ci/120cc...:jester:


----------



## wigglesworth (Mar 24, 2011)

cpr said:


> It seems this thing transfers through those holes in the piston skirt only. I need to pop the old jug and look at the case, because the ducts are there. If they're useable, this engine should wake right up if the case will permit.


 
There is also two different pistons for them. One, like yours, allows the jug to sit where the exhaust is pointed to the left or right, and another where the piston windows are open by the wrist pin, so the jug can sit with a forward facing exhaust. The jug can be rotated on the base, as long as you have the corresponding piston.


----------



## cpr (Mar 25, 2011)

wigglesworth said:


> There is also two different pistons for them. One, like yours, allows the jug to sit where the exhaust is pointed to the left or right, and another where the piston windows are open by the wrist pin, so the jug can sit with a forward facing exhaust. The jug can be rotated on the base, as long as you have the corresponding piston.


 
Correct. The guy I got this from asked which one I needed...


----------



## cpr (Apr 4, 2011)

*AH-81 Update*

Had time this am to pop the 81's jug. The weld repair was quite good on it, but there were other surprises inside.

Seems my decision to replace this jug was a good one, it was a ticking time-bomb. Sooner or later that piece was going to come loose and grenade the whole thing.







You can better see the piece I am refering to in this shot. The cracks continue between the transfers.






Cracked between transfers on the other side, too.






Seems there are more pistons and cylinders beyond the 90deg. change in exhaust port relative to thrust of piston...






The "old" piston is on the left, the "new" on the right. The corresponding transfer windows in the jug are also different. I port mapped the "old" jug and the exhaust and upper transfers are, for all intents and purposes, the same. The "old" lower numbers on the jug are .865 wide, 2.250 down to top and 3.140 down to bottom. On the piston, the "old" windows are .625 crown to top of port and .930 dia. While the old one's are significantly larger, I'm not porting out the "new" jug. This thing is quite thin and, apparently, brittle enough. I'll just be happy with it running rather than being a monster.

Lastly, the transfer ducts cannot be used as there is no place on the case to feed the charge to them.


----------



## promac850 (Apr 5, 2011)

Kart wait til dis id done... it scare dem littl kids off my lawn...


----------



## cpr (Apr 5, 2011)

Kickin' around looking for something and remembered ozflea having port maps for various McCulloch engines.

FYI

http://macbobaust.com/engine_specs.html


----------



## cpr (Apr 7, 2011)

"New" piston and cylinder are on the 81. Any idea what the torque spec is? I have it at 55 in/lb right now.

Also, the kill switch lead was flapping around behind the flywheel. I have no idea where it attaches. Could it be on the blade at the 4 o'clock position shown here?






Waiting on the bar tensioner and I have to go through the carb and get the oiler freed up and this one'll be ready.


----------



## leeha (Apr 7, 2011)

Not sure on the torque spec's, I usually
tighten till good and snug.
The kill wire will go to the stud the condenser
wire is on from the points.



Lee


----------



## cpr (Apr 7, 2011)

Thanks again Lee. I guess, ultimately, I'm less concerned with an actual number, but really want to be sure they are all equal as these seem to have a reputation for shaking loose (as the old jug is evidence of).

I seem to recall Mac head bolt specs in the 65-85 in/lb. range, FWIW.


----------



## cpr (Apr 9, 2011)

Found this in the original kart thread from 2004...

http://www.arboristsite.com/attachments/chainsaw/19228d1102509740-dolmar-gokart-pdf


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/yL3tobvL3rM" frameborder="0" allowfullscreen></iframe>


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/gPXdV3dI_W4" frameborder="0" allowfullscreen></iframe>


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/4EyxC4lo7tQ" frameborder="0" allowfullscreen></iframe>


----------



## RandyMac (Apr 14, 2011)

Fun vids Cliff, but I'm carsick now:msp_sad:


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/DRfPPi7mr5o" frameborder="0" allowfullscreen></iframe>


----------



## Mr. Bow Saw (Apr 14, 2011)

RandyMac said:


> Fun vids Cliff, but I'm carsick now:msp_sad:


 
LoL..You got to know when to stop.:msp_biggrin:


----------



## RTK (Apr 14, 2011)

Mr. Bow Saw said:


> <iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/4EyxC4lo7tQ" frameborder="0" allowfullscreen></iframe>




That is some serious fun to do


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/_nLzvx2RT3k" frameborder="0" allowfullscreen></iframe>


----------



## Mr. Bow Saw (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/qTX_a5Gvc2I" frameborder="0" allowfullscreen></iframe>


----------



## Mr. Bow Saw (Apr 14, 2011)




----------



## turtle561 (Apr 14, 2011)

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/3xHPkv5LyUs" frameborder="0" allowfullscreen></iframe>
german outboard, came as a single too.

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/YB4lXVMwnK8" frameborder="0" allowfullscreen></iframe>
another view of same race.


----------



## promac850 (Apr 14, 2011)

You guys are gonna get me in trouble... I got a bunch of slightly rusty angle iron laying around and a welder... and a 18 HP V-twin Briggs sitting in the barn... I might build my own kart!!!


----------



## rwoods (Apr 26, 2011)

*Kart Saw*

Here's a compression test shot of my 101B/125 that arrived today. I'll be looking for a flywheel as one of the fins is broken. Ron


----------



## cpr (Apr 26, 2011)

Nice, rwoods. Depending upon your starting technique, you may want to rotate that starter clockwise one set of holes.


----------



## rwoods (Apr 26, 2011)

cpr said:


> Nice, rwoods. Depending upon your starting technique, you may want to rotate that starter clockwise one set of holes.


 
I've been waiting at least a week for somone to notice but I guess the other MAC guys have drooled on their monitors so much they missed it. I can't help but wonder if this was done on purpose for racing where you begin with starting the saw. Or maybe the Seller had the foresight to know that my felling skills aren't the best so he adjusted the sights for me. Ron


----------



## rwoods (Apr 26, 2011)

cpr said:


> Nice, rwoods. Depending upon your starting technique, you may want to rotate that starter clockwise one set of holes.


 
Nobody has mentioned the Stihl starter grip either. Ron


----------



## rwoods (Apr 26, 2011)

*Here's another.*

Just sold: McCulloch 125 / 125 C Chainsaw with Stihl File | eBay

Ron


----------



## stinkbait (Apr 27, 2011)

cpr said:


> Nice, rwoods. Depending upon your starting technique, you may want to rotate that starter clockwise one set of holes.


 
I have mine rotated the same way because it allows me to pull straight up when starting the saw on the ground.


----------



## Ambull (Apr 27, 2011)

rwoods said:


> I've been waiting at least a week for somone to notice but I guess the other MAC guys have drooled on their monitors so much they missed it. I can't help but wonder if this was done on purpose for racing where you begin with starting the saw. Or maybe the Seller had the foresight to know that my felling skills aren't the best so he adjusted the sights for me. Ron



I noticed right away, but who am I to tell you how to start your saw. Just by aesthetics it would look better, as the rotation would straighten out the embossed logo. I actually like starting mine on the ground, with one foot on the handle. Mine doesn't have compression release, so I really have to grunt and pull. At your angle a ground start is a bit easier.


----------



## promac850 (Apr 27, 2011)

My technique would love that set up too... I usually have the saw on the ground too. I can see how on a beast of a saw like that with monster compression would be more favorable to start on the ground... sure, the logo isn't exactly in the right place, but it looks like it would be easier to start clocked that way.

In the end, it's up to you and how you start it. If it's more comfortable on the ground, the way it is now will be best, if you are crazy enough to drop start it and dip the bar tip into the ground, then clocking it so the logo looks perfect would be the way to go.


----------



## rwoods (Apr 27, 2011)

I plan to line it back straight. This is just how it was pictured on eBay and received by me. It sure made the compression testing easier though. Ron


----------



## cpr (Apr 27, 2011)

Yeah it'd be great for the comp test, but, for me anyway, would suck for starting. I prefer to prop it up on a stump, log, picnic table, whatever when I start and more of a pull back than up. It's easier to operate the throttle and choke controls when starting.


----------



## rwoods (Apr 27, 2011)

101B - what is the mix ratio? From some MAC materials furnished me it appears to be 20 to 1. No mention of MAC oil which in saw manuals usually is stated at 1/2 the non MAC oil mix. Thanks, Ron


----------



## Jacob J. (Apr 27, 2011)

You can go with 40:1 if you're using a high quality oil. The last running kartsaw I had I ran 32:1 w/Silkolene.


----------



## rwoods (Apr 27, 2011)

Jacob J. said:


> You can go with 40:1 if you're using a high quality oil. The last running kartsaw I had I ran 32:1 w/Silkolene.


 
Thanks


----------



## Brian13 (May 17, 2011)

Been doing some looking around, and are there any major differences between the various 101 models that make one more or less desirable for kart saw builds?


----------



## cpr (May 17, 2011)

Great question Brian. One I've considered as well. So far as I can make out, the "b" certainly is the most plentiful and therefore perhaps most desireable because the die-hard collectors/racers are after the rarer ones...

Although, as plentiful as the "b"s are, finding an unmolested example is quite a challenge. Lot's of them seem to be boogered, ported, or both.


----------



## Brian13 (May 17, 2011)

I was talking with another member and he was saying he thought something about the mounting holes on the 101aa woundnt work for saw purposes. In my research I havnt found any major differences though. I was thinking the blocks themselves were pretty much the same.


----------



## cpr (May 17, 2011)

Don't know if you've seen this chart on the known differences. McCulloch Championship Kart Racing Engines .............


----------



## Brian13 (May 17, 2011)

That what I was looking at, and I dont see any major differences. As far as I can tell it looks like they are all pretty close.


----------



## cpr (May 18, 2011)

I don't want to run afoul of the mods for this, so you guys will have to google the place yourselves, but you can save a little time and shopping when rebuilding Super 44A/55A, 1-70/80, 1-71/81, and 1-72/82 saws by buying a bearing and seal kit for the bottom end and a gasket kit for the MC-10 that will get you the inner stuffer gasket, head gasket, and intake gaskets (some of which may not work for the saw induction tract) all in one shot. Also applies for the kartsaw guys with 91s and 101s... I did order a gasket kit for my 101 build, cheaper than individually on feebay. 

It is strictly a kart supplier, they don't mess with saws or ***.

I thought it was handy, so I'm passing it along.


----------



## terry2tmd (May 24, 2011)

Just subscrideing this is great stuff!!!!!


----------



## Busmech (May 24, 2011)

Brian13 said:


> Been doing some looking around, and are there any major differences between the various 101 models that make one more or less desirable for kart saw builds?


 
The original 101's had the removable boost ports and the pistons did not have the large cutout for the boost port. The rod also was different with the 9/16ths wrist pin but the later piston and rod will work. The rest are pretty much the same except some of the 101c's and d's were chrome bore I think but not sure on that.


----------



## Busmech (May 24, 2011)

Also I forgot the original 101 had a bridged exhaust.


----------



## rwoods (May 24, 2011)

Believe it or not but I got a question that has stumped some of us over in the MAC thread. My 101B's connecting rod slides so far off center when the engine is flywheel down that it binds on the crank so much so you can't turn the crank without some leverage. It also binds just a tad when the saw is held clutch side down. What do I need to fix this? New rod bearings, wrist pin bearings, new rod, all, some or none? Thanks, Ron


----------



## Jacob J. (May 25, 2011)

Ron-

Sounds like you may need new bearings on both ends of the rod and a wrist pin as well. Check the tolerances for the rod- if it's that far out of whack you may need to replace the rod.


----------



## cpr (May 25, 2011)

Neat article reprint from 1959 on the MC-10 development.

McCulloch's Entry into Kart Racing


----------



## OREGONLOGGER (May 25, 2011)

Great piece on the MC-10 engine, I just came across a very strong running Super 55A saw that's in great shape. Now I know why everyone's bugg'n me for it:hmm3grin2orange:


----------



## Pendagator (Aug 20, 2011)

*Don Knotts and McCulloch Karts*

In case you haven't seen it, this is pretty cool. McCulloch Kart Promotion Movie circa 1961 - YouTube


----------



## turtle561 (Aug 20, 2011)

go barney, go !


----------



## Eccentric (Aug 20, 2011)

*Sorry if this has been posted before here..........*

....but I saw this on youtube after watching the 'Barney' McCulloch spot. Cool stuff...



Vintage Karting New Castle 2011 1st Heat McCulloch MC49 - YouTube


----------



## NORMZILLA44 (Aug 21, 2011)

Wonderfull thread Great video's that one in the 60's imagine racing one those thing's haul ass! I gonna burn some midnight oil the 2101 is coming apart I am building a go cart LOL!


----------



## Eccentric (Aug 21, 2011)

NORMZILLA44 said:


> Wonderfull thread Great video's that one in the 60's imagine racing one those thing's haul ass! I gonna burn some midnight oil the 2101 is coming apart I am building a go cart LOL!


 
There've been a few 'vintage' Rupp and McCulloch kart and kart engines/parts listings on our local CL over the last few months Norm. If I had the money......


----------



## NORMZILLA44 (Aug 21, 2011)

That stuff is just way cool When I was a kid I had we had a couple go kart's but nothing that cool, or that fast! That was what I wante'd. I love it Nostalgia.


----------



## Eccentric (Aug 21, 2011)

NORMZILLA44 said:


> That stuff is just way cool When I was a kid I had we had a couple go kart's but nothing that cool, or that fast! That was what I wante'd. I love it Nostalgia.


 
The Sebastopol flea market property used to be a Kart track in the 60s and early 70s. I can remember going to the flea market as a kid and seeing a couple derilict Karts in the weeds. Nobody wanted them then...

In Santa Rosa, a guy over on whatever road starts with a "C" that goes between Santa Rosa avenue and Petaluma Hill road (can't remember right now dammit) ran a kart shop out of his garage. Near the backside of where Best Buy and all that is now. Over near where the Raiders used to have their practice field. Think that little shop closed down around 1983-1984 or so. I still remember seeing SHELVES of McCulloch Kart engines in his garage.......and I was only 10 at the time. Was getting small parts for an old B&S powered go kart I had at the time...


----------



## NORMZILLA44 (Aug 21, 2011)

Wow, never knew that about the flea market. I can't think of the road name either, but know where you are talking about. I remember when go kart's were a real big deal! Glad they still are.


----------



## turtle561 (Aug 21, 2011)

i lived in lafayette and ran a bug kart in the east bay area in the early 60's. it had a clinton a-490 on it. i remember the sounds of the macs and homelites that dominated the scene then. i'm starting to look at my 55 with a new eye now.which mac is it kartwise ? i've seen it on here somewhere. lot of fun. really enjoyed the videos !
i think cotati was one of the places we ran. martinez too.


----------



## NORMZILLA44 (Aug 21, 2011)

Turtle561, small world laffyette are is beautifull. We hunt in Moraga, I work in cotati. I would love to see more kart video'sopcorn:


----------



## Eccentric (Aug 21, 2011)

turtle561 said:


> i lived in lafayette and ran a bug kart in the east bay area in the early 60's. it had a clinton a-490 on it. i remember the sounds of the macs and homelites that dominated the scene then. i'm starting to look at my 55 with a new eye now.which mac is it kartwise ? i've seen it on here somewhere. lot of fun. really enjoyed the videos !
> i think cotati was one of the places we ran. martinez too.


 
The Sebastopol track was sepperate from the Cotati track. People were really spoiled here as far as Kart tracks are concerned methinks. The tracks were probably less than 10 miles apart. I've heard that Petaluma had a Kart track at one time as well. I don't know if all these tracks were up and running at the same time. Closest Kart track I know of now is near Dixon. That's about 1.5 hours away from here.


----------



## NORMZILLA44 (Aug 21, 2011)

Aaron I vaguely remeber one in Petaluma too. Seem's to me when I was about thirteen they turne'd it into a track for R.C Car's. Been a long time.


----------



## turtle561 (Aug 22, 2011)

*old school macs*

eccentric and normzilla- heres one that resonates: Vintage Kart racing at Ocala Florida Track - YouTube


----------



## Eccentric (Aug 22, 2011)

Cool! Makes me wish I was 20 years younger and 50 pounds lighter.


----------



## rwoods (Aug 22, 2011)

turtle561 said:


> eccentric and normzilla- heres one that resonates: Vintage Kart racing at Ocala Florida Track - YouTube


 
I grew up in Ocala. On Sundays in the late sixties, the go-karts would race behind the old Brahma restaurant. I believe a lot of them were MAC powered. Ron


----------



## rwoods (Sep 25, 2011)

*I have a lot to learn.*

I fired up my little red 101B today. (pictures here http://www.arboristsite.com/chainsaw/172208-7.htm and in MAC thread). I don't have enough hands between stabilizing the bench and cranking it. I am glad I only had 10ccs of fuel in the line after the carb quit bubbling air as when it cranked it screamed until the fuel ran out. I just barely had the throttle above idle. I put another 10 ccs of fuel in it this time leaving the carb at idle - same result. Do you think the vacumn is overcoming the throttle spring (I don't have any linkage)? The spring seems to be of normal tension. Or is there sometime else I am missing? It gulps the fuel down in seconds although it seems like an eternity as I gather my wits and remind myself there is no off switch. Thanks for your help. Ear protection is going to be a must with this baby. Ron


----------



## Eccentric (Sep 25, 2011)

rwoods said:


> I fired up my little red 101B today. (pictures here http://www.arboristsite.com/chainsaw/172208-7.htm and in MAC thread). I don't have enough hands between stabilizing the bench and cranking it. I am glad I only had 10ccs of fuel in the line after the carb quit bubbling air as when it cranked it screamed until the fuel ran out. I just barely had the throttle above idle. I put another 10 ccs of fuel in it this time leaving the carb at idle - same result. Do you think the vacumn is overcoming the throttle spring (I don't have any linkage)? The spring seems to be of normal tension. Or is there sometime else I am missing? It gulps the fuel down in seconds although it seems like an eternity as I gather my wits and remind myself there is no off switch. Thanks for your help. Ear protection is going to be a must with this baby. Ron


 
Wire the throttle arm in the idle possiton to be sure. Look through the carb throat and see if the throttle is indeed closed at idle. Could be adjusted quite a bit past closed. Doesn't take much to make an unloaded engine rev up. If you close the throttle and wire it in that possiton and the engine still revs to the moon........................then you have an air leak somewhere my friend.

You can make an OH ####!!!!!! handle out of a couple of zip ties attached to the plug cap. If the engine's revving towards destruction............pull the hell out of the zip tie to get the plug cap off of the plug. You may break a spark plug wire, but that's FAR better than throwing a rod...


----------



## cpr (Sep 25, 2011)

Uh... Well, I don't know how you mounted it, but if the head was finger tight, any chance the stuffer is the same and that's your air leak?

Like Aaron said, what's the throttle butterfly doing?


----------



## rwoods (Sep 25, 2011)

After I posted I started thinking air leak at the stuffer but I don't know. The butterfly is barely cracked - don't know when running as it :msp_scared: me bad then was done before I could react. I have it bolted through the stuffer to my bench. I'll either build a leak tester and/or a shorting wire to shut her down. It definitely sounds like it is hitting rpm levels previously unknown to me. Thanks, Ron


----------



## cpr (Sep 25, 2011)

Again depending on how you mounted it, is there an oil tank? If not, do you have a saw stuffer in there and it's getting a big gulp of air through the auto-oiler impulse port?


----------



## rwoods (Sep 25, 2011)

Kart stuffer - no oil hole yet. Ron


----------



## NORMZILLA44 (Sep 27, 2011)

Kart engine, I just love the name what a ring to it!


----------



## Brian Thomas (Nov 24, 2011)

Mr. Bow Saw said:


> <iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/qTX_a5Gvc2I" frameborder="0" allowfullscreen></iframe>



That is our kart . That motor is a AH61 that is .060 over and has a stroker crank in it .

I found this site while doing some surfing .

Check out our site 

Black Dog Vintage Racing

We run Power Products exclusively .

Brian


----------



## blsnelling (Nov 24, 2011)

Brian Thomas said:


> That is our kart . That motor is a AH61 that is .060 over and has a stroker crank in it .
> 
> I found this site while doing some surfing .
> 
> Brian



Beautiful kart there Brian! You could have a nuclear explosion in that engine and it wouldn't blow the head off Welcome to the forum


----------



## Trever (Nov 24, 2011)

*West Bend Model 2736*

The West Bend model 2736 is essentially a model 700 with a shorter stroke (105cc). This is what my late 1950s Strunk Big Machete has on it. I will post the specs when I find them. Have a blessed abnd happy Thanksgiving.


----------



## cpr (Nov 28, 2011)

Missed out on a 48890b carb with a GEM elbow and a REED sloper intake on feebay tonight. Oh well, whoever got them had to open their wallet a little anyway :msp_biggrin:.

I got some trees to bark up for that stuff...


----------



## leeha (Nov 28, 2011)

I watched that as well.
But it wasn't me.

I have an intake for the BDC carb
for my next kart saw. Thanks the Jacob J.



Lee


----------



## cpr (Dec 10, 2011)

Cleaning up the shop tonight and had to take a pic of 362cc of American muscle, two of which are kartsaws.





View attachment 210849


----------



## Rounder (Dec 10, 2011)

Nice to see you're still at it. I've got two boxes of big yellow in the shop waiting for me....if I ever get a spare moment.


----------



## rwoods (Dec 13, 2011)

As some may recall, my kart saw's connecting rod would bind when the saw was turned on its side. I have now removed *all* of the bearings. Is there anything this neophyte should know before installing any of the new bearings? Also is there any chance a crank could be slightly bent? If so, how can this be detected before reassembly? The connecting rod appears to be nice and straight when placed against a straight edge. The wrist pin bearings don't seem any looser than the new ones and the main bearings didn't appear to have any unusual slop. The wrist pin measures between .4985 and .499. Thanks, Ron


----------



## cpr (Dec 13, 2011)

I suppose it's possible. I don't know how they made these old cranks. If they're interference fit for the rod journal like modern cranks the throws might be out of clock with each other???

Good luck Ron, hope you get it going.


----------



## leeha (Dec 13, 2011)

Ron, When the motor is together, Do you have a bit of
side play on the rod. Is the crank floating in the case bores.
Sounds like the crank is moving. These cranks are a cast
crank. If it were out of time it would be twisted and you would
know it no matter the position of the saw.




Lee


----------



## rwoods (Dec 13, 2011)

leeha said:


> Ron, When the motor is together, Do you have *a bit of
> side play on the rod*. Is the crank floating in the case bores.
> Sounds like the crank is moving. These cranks are a cast
> crank. If it were out of time it would be twisted and you would
> ...



Lee, before disassembly I didn't detect any crank play. The rod had enough side play to bind. Should I have the crank's rod bearing surface checked by a machine shop? I have a set of new needle bearings which I'll install with the rest of the bearings. Thanks, Ron


----------



## leeha (Dec 13, 2011)

Did the rod bind on the crank with the old needles.
I would take the crank out and assemble the rod to
the crank and see if it binds. Try this with the new 
needle bearings as well as the old ones. The rod
should spin around the crank nice and smooth no
matter what.



Lee


----------



## rwoods (Dec 13, 2011)

Lee, it would bind with the old needles. The rod would slide to the side and bind. You could give it a little jerk and it would pop and free itself. You could also just push the rod back over with your thumb. I disassembled the entire engine some months ago and bought all new seals and bearings. I had a little time tonight so I pulled all the old bearings. I guess I'll just go ahead and install the new and see how everything fits. Anything I should know first? Thanks, Ron


----------



## leeha (Dec 14, 2011)

I'm not sure what to say Ron without seeing it.
But if you move the rod to one side and i binds,
Something ain't right. I would really inspect the crank
and polish the journal with extra fine emery paper as
well as the rod bearing surface. Just make sure you 
use FINE paper.




Lee


----------



## heimannm (Dec 14, 2011)

Is that one supposed to have thrust washers in the piston end to keep the rod from moving "side to side"?

Mark


----------



## rwoods (Dec 14, 2011)

heimannm said:


> Is that one supposed to have thrust washers in the piston end to keep the rod from moving "side to side"?
> 
> Mark



Mark, none shown on the IPL. I think I'll have a machinist look at the crank and let me know what he thinks. If okay, I'll have him press on the bearings. 

Anyone know the proper diameter for the journel? 

Thanks, Ron


----------



## Brian13 (Dec 14, 2011)

I had the same problem on my Super 250 when I was putting it together. About an 1/8th of a turn past BDC and it would bind with the big end of the rod going to one side of the crank. Push it back to center and it would go freely. With the case cover off it would go full rotation smoothly. Never really figured out what was causing it. Figured it had something to do with the bearings and how they were pressed in, because it would be smooth until I got the bolts on the case cover tightened down. I could loosen the case cover bolts a little and it would lessen the binding as well. After taking it apart and putting back together again many times eventually stopped, and so far I have not had any problems. If I did anything that had any effect on it was tapping the crank on either side.


----------



## rwoods (Dec 14, 2011)

Brian13 said:


> I had the same problem on my Super 250 when I was putting it together. About an 1/8th of a turn past BDC and it would bind with the big end of the rod going to one side of the crank. Push it back to center and it would go freely. With the case cover off it would go full rotation smoothly. Never really figured out what was causing it. Figured it had something to do with the bearings and how they were pressed in, because it would be smooth until I got the bolts on the case cover tightened down. I could loosen the case cover bolts a little and it would lessen the binding as well. After taking it apart and putting back together again many times eventually stopped, and so far I have not had any problems. If I did anything that had any effect on it was tapping the crank on either side.



Sounds very familiar. Thanks. We will see how it does with all new bearings. Ron


----------



## cpr (Jan 4, 2012)

McCulloch 5 deg. flywheels. Here's the difference.

0 Deg.






5 Deg.





That's it. I won't pretend to know anything about electrcal stuff or how these systems work, but it is counterintuitive to me that a 5 deg. advance flywheel would have 1 distinguishing characteristic located 5 deg. retarded from a supposed 0 deg. flywheel... Other than the 5 stamping, there's no other differences.


----------



## petlele7456 (Jan 4, 2012)

Great pics, this thread is looking better and better.


----------



## cpr (Jan 4, 2012)

Here, too?!?!

Looks like you're full of red paint, but have some more.

EDIT: Nevermind, looks like he's everywhere.


----------



## cpr (Jan 5, 2012)

Side by side. 5 deg. on the right.


----------



## leeha (Jan 5, 2012)

Nice info.




Thanks Lee


----------



## cpr (Dec 8, 2012)

Jacob J. said:


> No, higher RPM doesn't translate necessarily into higher HP automatically. I actually prefer in many cases, the saw blocks, especially in larger displacement. My latest project involves cutting the heads off of three SP-125 blocks, having them bored out .050" over and chromed, and then fitting custom heads to them. Two will get all-new manufactured heads while the third will get a custom WB-820 head that has larger cooling fins.
> 
> Another of my kooky ideas involves a Homelite 990 saw chassis, an Mc-7 crank, an Mc-90 .010" over domed piston (thin rings), an Mc-93 rod, and a Mikuni 34mm carb. It's a witches' brew but might make a good runner.



Was digging for something else and remembered this...

opcorn:


----------



## ozflea (Dec 8, 2012)

A rather simple tool i made from a piece of flat bar and a cut off crankend 






McBob.


----------



## Brian Thomas (Mar 11, 2013)

Power Products AH82


----------



## leeha (Mar 11, 2013)

That thing is sick lookin.
I got a few saws that would bolt right into.






Lee


----------



## RTK (Mar 11, 2013)

Looks like a glow engine


----------



## cpr (Mar 11, 2013)

Nice looking 8.1. Got any pictures of how the head is setup on it?


----------



## Brian Thomas (Mar 11, 2013)

It's a AH82 . 

I have to cut the chamber and drill and tap the jug .

Also I need to cut the boost ports deeper


----------



## ozflea (Mar 11, 2013)

Fitted with a Copperhead US820 Kart Engine @134cc






McBob.


----------



## Brian Thomas (Mar 11, 2013)

Hi Bob 
Have you had the head off of that copper head yet ?
I was wondering what the combustion chamber design looks like .
If the squish is around 50 % of the surface area ( .625" on each side of the chamber ) and the chamber is around 5cc I would like to copy that style for our 82 heads .


----------



## ozflea (Mar 11, 2013)

Brian Thomas said:


> Hi Bob
> Have you had the head off of that copper head yet ?
> I was wondering what the combustion chamber design looks like .
> If the squish is around 50 % of the surface area ( .625" on each side of the chamber ) and the chamber is around 5cc I would like to copy that style for our 82 heads .



Yes Brian i have but no pics on here sorry 

McBob


----------



## cpr (Mar 11, 2013)

Nice website Brian. What can you tell me about the kart under the Quincy 2011 event photos with what looks like an MC-91 with dual carbs fed through the flywheel housing? Never seen a setup like that. Some sort of pull-through carb supercharger?


----------



## Brian Thomas (Mar 11, 2013)

Mac custom built rotary valve . Uses a modified circular saw blade for the rotary valve


----------



## leeha (Mar 11, 2013)

Some very nice stuff Brian.
Thanks for sharing. I'm very impressed
with all the Power Products motors.


----------



## Brian Thomas (Mar 11, 2013)

View attachment 283992
1961 Simplex with dual AH 58 Power Products

View attachment 283989
1961 Fox with dual AH58 supers 

View attachment 283990
The wife and I on the grid at Delmar Iowa 2012


----------



## Bingo (Mar 11, 2013)

*Kart engines*

Great thread here. Getting sidetracked by all the vintage karts!...Remember walking into Troy Ruttman's go-kart shop on Ford Rd., in Dearborn about 1961-2 and thinking I'm just in heaven...Couldn't afford to go racing but he was a good guy and it was all karts all the time. Those Macs were king at the time. Glad there's some still around. So glad this thread was brought up to date. Like to see more. Loved karts then but that was big $$$ to a 16 yr old. Still nice to see them. Gonna have to spend some time at the local kart track this summer...when I'm not looking for firewood, of course. Thanks to all for the great nostalgia.


----------



## ozflea (Mar 12, 2013)

When one angry Mac is not enough 





McBob


----------



## Bill G (Mar 12, 2013)

Brian Thomas said:


> View attachment 283990
> The wife and I on the grid at Delmar Iowa 2012



Brian,

Will you be at Quincy this year? I planned on Delmar last year but missed it being early


----------



## Brian Thomas (Mar 12, 2013)

We will be there . We pit by the track exit.


----------



## cpr (Mar 12, 2013)

Brian Thomas said:


> Mac custom built rotary valve . Uses a modified circular saw blade for the rotary valve



That was my second thought. Feeds through the bottom then? Not much flywheel effect, but I bet it's a rev-gaining monster. Neat bit of fabrication. Battery is there because there's no magneto?


----------



## Brian Thomas (Mar 12, 2013)

cpr said:


> That was my second thought. Feeds through the bottom then? Not much flywheel effect, but I bet it's a rev-gaining monster. Neat bit of fabrication. Battery is there because there's no magneto?



Correct no mag


----------



## 67L36Driver (Jun 10, 2013)

Worth looking at? McCulloch Go Kart/WTT


----------



## moody (Jun 10, 2013)

67L36Driver said:


> Worth looking at? McCulloch Go Kart/WTT



Yes Mac made some damn fine karts!


----------



## Brian Thomas (Jun 10, 2013)

67L36Driver said:


> Worth looking at? McCulloch Go Kart/WTT



I don't think its a Mac kart but still worth checking out . Pix would help on ID.


----------



## barneyrb (Jun 10, 2013)

Brian Thomas said:


> I don't think its a Mac kart but still worth checking out . Pix would help on ID.



Your site is just way cool. I wish karts had been popular around here years ago. They never caught on in Louisiana, mostly dirt cars.......


----------



## Brian Thomas (Jun 10, 2013)

We took our karts to the Billetproof car show.

all Power Products motors 






I was doing some mock up work on the blue Fox kart so we took it with .

Dual AH82 .030 over dual carb alcohol motors 





We are getting pretty close to the final assembly on the kart and motors .

Brian


----------



## leeha (Jun 10, 2013)

Brian, Thoses motors are sick. Must
be a far cry from a saw motor. I like
the removable head design. Any idea
on HP ratings.




Lee


----------



## Brian Thomas (Jun 10, 2013)

I don't know what they would put out . I saw a good set of 82s will give a pair of 101s a run .
They would pull the 101s out of the corners 

You cant tell I have a thing for Power Products , can you ?


----------



## heimannm (Jun 25, 2013)

I am getting started on my 101AA saw project, looks like I will need a piston and rings. Options are:

84473 & 66047 +0.020
84474 & 66045 +0.030
84476 & 69469 +0.050

Any help or suggestions will be most appreciated.

Mark


----------



## Brian Thomas (Jun 25, 2013)

heimannm said:


> I am getting started on my 101AA saw project, looks like I will need a piston and rings. Options are:
> 
> 84473 & 66047 +0.020
> 84474 & 66045 +0.030
> ...



Look up Terry Ives industries . He might be able to help you out.


----------

