McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
Help Support Arborist Forum:
Should have the 797 next Monday.
I'm planning to build a separate cart saw this winter. Should be a lot of fun. I'm thinking maybe even some powder coating and chrome for it. I believe the base saw will be a SP125. Any special parts I'll want to keep my eyes open for?
I'm planning to build a separate cart saw this winter. Should be a lot of fun. I'm thinking maybe even some powder coating and chrome for it. I believe the base saw will be a SP125. Any special parts I'll want to keep my eyes open for?
cpr
Addicted to ArboristSite
Glad to see you playing in here Brad, these things are like crack. I love your builds and look forward to you tackling a kart-saw.
The good part about yellow fever is the saws and karts are so plug-and-play, you have a TON of options. Special parts come in to play more on restos (your 797 will be easy, though). The frankensaws have "possibilities."
BTW, I'm uploading vids right now... Haven't put a stopwatch to the vids, but I'm fairly certain the 791R humiliated the 1-72 and the Super 797...
Glad to see you playing in here Brad, these things are like crack. I love your builds and look forward to you tackling a kart-saw.
The good part about yellow fever is the saws and karts are so plug-and-play, you have a TON of options. Special parts come in to play more on restos (your 797 will be easy, though). The frankensaws have "possibilities."
BTW, I'm uploading vids right now... Haven't put a stopwatch to the vids, but I'm fairly certain the 791R humiliated the 1-72 and the Super 797...
Thanks CPR. Hopefully I won't drive you guys to crazy with my enthusiasm and obsessiveness, lol.
About some of these options, what's this V4 reed block I've seen mentioned?
Off the top of my head, You will need
a SP125 saw, 101 motor, BDC carb, Not
the double pumper, And a sloper intake.
This is if your going to keep it stock appearing.
Lee
I believe I've seen mention of 101A and 101B engines. Make much difference? I believe I've also read to watch out for using one too modified, ruining it for a proper chainsaw powerband. Tell me about this
V4 and sloper.
cpr
Addicted to ArboristSite
V4 is the reed layout. Gives better flow than the flat plate deuce in the saws and is more like a dirtbike's. For dual carbs, there's the GEM V-12
.
The sloper will let you mount a BDC carb inside a SP125 airbox if you cut the bottom of the box out. mcbob has a race saw this way and leeha, rwoods, and myself all have kart builds on the bench setup this way.
For the differences in MC-101 A/AA/B/C/D/M, go here: McCulloch Championship Kart Racing Engines ..............
McBob has a TON of info on all things Mac there.
.The sloper will let you mount a BDC carb inside a SP125 airbox if you cut the bottom of the box out. mcbob has a race saw this way and leeha, rwoods, and myself all have kart builds on the bench setup this way.
For the differences in MC-101 A/AA/B/C/D/M, go here: McCulloch Championship Kart Racing Engines ..............
McBob has a TON of info on all things Mac there.
I don't think you will go wrong with any of the 101 motors.
The most popular is the 101B but then i believe everyone
that owns one thinks it's a B when it could be any of the
others, They all look the same.
Definately go for a stock motor. Then do with it what you want.
I prefer 101's that are already in saws because they will have minimal
damage, stock bores and ports from what i have seen. Engines that
have been raced on karts for the most part have been raced to hell
and back with chain rash, Broken bolt bosses, stripped bolt holes,
Bored and ported to death.
Lee
The most popular is the 101B but then i believe everyone
that owns one thinks it's a B when it could be any of the
others, They all look the same.
Definately go for a stock motor. Then do with it what you want.
I prefer 101's that are already in saws because they will have minimal
damage, stock bores and ports from what i have seen. Engines that
have been raced on karts for the most part have been raced to hell
and back with chain rash, Broken bolt bosses, stripped bolt holes,
Bored and ported to death.
Lee
Brad, from my research you can go one of two routes for a stock appearing 101B SP125. Easiest and closest to factory (if there really is such a thing as a factory 101B chainsaw) - just replace the 125 engine with a 101B, tap in a DSP, use a fully adjustable SDC carb, and a 797 muffler. For a hotrod with no air filtration - cut out the inside of the tank, use a sloper 4v intake with a single pumper 35 mm BDC carb and a 797 muffler (see page 4 of McCulloch Algebra). I hope to have one of each when I get time: a .050 over with the SDC and a .030 over hotrod with the BDC; I'll probably skip the DSP and use a kart muffler instead of the 797 muffler on the hotrod (no one around here knows what a SP125 is supposed to look like anyway).
If you are patient enough unmolested 101B's come up for sale from time to time but most will at a minimum have some fin damage. I was able to find and purchase a sloper manifold off a kart forum. If you buy an engine from a karter, just remember that they take these things apart all the time. I couldn't get mine to run at first only to find the head bolts were just loose enough to lose some compression then I couldn't shut it down when I cranked it because the manifold bolts were just loose enough to suck air.
Ron
If you are patient enough unmolested 101B's come up for sale from time to time but most will at a minimum have some fin damage. I was able to find and purchase a sloper manifold off a kart forum. If you buy an engine from a karter, just remember that they take these things apart all the time. I couldn't get mine to run at first only to find the head bolts were just loose enough to lose some compression then I couldn't shut it down when I cranked it because the manifold bolts were just loose enough to suck air.
Ron
cpr
Addicted to ArboristSite
Glad you solved the mystery, Ron. I was wondering if you got to the bottom of that.
Personally, I wouldn't bother with the DSP. The 791R is 99cc and 185 compression and really isn't that tough to start. Just use the mass of the saw to your advantage, and, as always, find tdc/pull it like ya' mean it. My 288 at 170 compression (no decomp either) is actually harder to start (lighter).
Couple tuning issues to sort on the 791R, and one small side project to blow out, then the SR-101 starts...
Personally, I wouldn't bother with the DSP. The 791R is 99cc and 185 compression and really isn't that tough to start. Just use the mass of the saw to your advantage, and, as always, find tdc/pull it like ya' mean it. My 288 at 170 compression (no decomp either) is actually harder to start (lighter).
Couple tuning issues to sort on the 791R, and one small side project to blow out, then the SR-101 starts...
Excellent info! I love a post like this.
I'm definately going for a straight hotrod build. I've got a SP125, 101B block, and BDC carb headed this way, thanks to one of you great guys. That means I'm on the search for a sloper intake and a V4 reed cage. Anyone have a lead on one? I'm sure I'll need more odds and ends as I go, but this will sure get me started.
Anyone have a reputable shop they've used to bore out a block? The block is coming with a .030" over piston, and I'm hoping that will clean it up.
I have a machine shop 40 minutes from me that
doe's all mine. He has done at least a half dozen
for me in the past two years. 80 bucks is his price.
You should be able to find a machine shop near you.
The 101 blocks are not hard with the removable head.
Lee
doe's all mine. He has done at least a half dozen
for me in the past two years. 80 bucks is his price.
You should be able to find a machine shop near you.
The 101 blocks are not hard with the removable head.
Lee
Brian13
Addicted to ArboristSite
Good on you Brad, diving right in. Your making me jealous. You making this a work saw build or full on hotrod? The 101s sound awesome with a pipe
. If you need any IPls shoot me a PM.
. You making this a work saw build or full on hotrod? The 101s sound awesome with a pipe. If you need any IPls shoot me a PM.
Good on you Brad, diving right in. Your making me jealous
Just a fun hotrod. I'd love to have IPLs for the SP125 and 797.
Brian13
Addicted to ArboristSite
Shoot me your email address.
You guys are great! Thanks, Brian, for the IPLs and other links.
54stude
ArboristSite Operative
I think it took Brad less than a week to catch yellow fever!
Brian13
Addicted to ArboristSite
No problem!! Glad to help.
cpr
Addicted to ArboristSite
HAHA. Yellow is going to start spreading across his sig like an infection after he tries that kartsaw...
One thing I just thought of. When you rebuild the BDC, there's a duckbill valve in there that is close to unobtainium. I can't remember off the top of my head, but there was a kart parts dealer somwhere that had some and, I believe, there is a Homelite one that can be had easier that will fit. Sorry, don't have the details to hand as I haven't gotten into that one just yet.
Similar threads
Want to Sell
Vintage Collection Liquidation
