McCulloch Chain Saws

[Jethro 2t sniffer]

i go for the bigger power myself even if its not needed just cause i want to

Sent from my VS995 using Tapatalk

Yeah I agree.

Either one of you ever ran a SP125C? That's big power and surprisingly very manageable power. Not a hard to handle beast that one would think. Very easy saw to run but will break you down to carry.

Brian

a 125 would be rather nice. I imagine it's a bit like a cr500 really nice fat smooth power and can really be nice and manageable up hills n stuff or lugging around behind the kids. Not really the savage beasts there made out to be. A cr125 will throw you off the back up a hill far easier as you need to keep it singing lose momentum and your fighting the front wheel or out of the power and stopped

 

[RolandM]

The piston on the right above is 85240 which was used in the early model (suffix A and B) 6-10A saws. Later models (C, D, E, and F) all used 85239. It was remembering that piston that made me follow up on the early 7-10 models. The 6-10 IPL also shows the piston with the open skirts but as you can see, the earlier piston (85240) is quite different and make me wonder what the 69030 really looks like. The illustrations in the IPL's are not totally accurate, but the piston that Kevin pulled from the saw did look to have the open skirts like the 85239.

The impulse passage is clean and open as I checked it several times. I did replace both insulators (between the cylinder and the air box, and between the air box and the carburetor as well as replace the gaskets just to make very sure everything was hunky dory.

Kevin - was there anything else you might have changed while working on the saw, even something insignificant?

Mark

And a P.S., when I opened up my later model 7-10 with the pop up compression release it had the thick rings, I remember because I broke one trying to reinstall the piston not realizing it was fit with locating pins...the IPL's would all have you believe that saw should have the 85239 with thin rings although the 1974 IPL lists both thin and thick rings even with the 85239 piston listed.

Hi Mark,

A replacement piston which does not cover the intake port properly will cause mayhem with low speed running. Likewise a shorter piston skirt will change timing and this could spoil the idle. Check the cylinder to bore fit too. A loose fit will give poor sealing of the intake in the same manner a terribly worn piston will also do.

Roland.

 

[Kevin hayes]

Yeah I agree.



a 125 would be rather nice. I imagine it's a bit like a cr500 really nice fat smooth power and can really be nice and manageable up hills n stuff or lugging around behind the kids. Not really the savage beasts there made out to be. A cr125 will throw you off the back up a hill far easier as you need to keep it singing lose momentum and your fighting the front wheel or out of the power and stopped

hmmm somebodys thinking dirt bikes

Sent from my VS995 using Tapatalk

 

[PogoInTheWoods]

The piston on the right above is 85240 which was used in the early model (suffix A and B) 6-10A saws. Later models (C, D, E, and F) all used 85239. It was remembering that piston that made me follow up on the early 7-10 models. The 6-10 IPL also shows the piston with the open skirts but as you can see, the earlier piston (85240) is quite different and make me wonder what the 69030 really looks like. The illustrations in the IPL's are not totally accurate, but the piston that Kevin pulled from the saw did look to have the open skirts like the 85239.

All of the piston and ring set reference material I have from '63 - '82 lists the 69412 piston for the 4-10 thru the LG-6 even though the '72 6-10A IPL (the only 6-10 IPL I have) indeed indicates it supersedes all previous 6-10 parts lists and includes both 85240 and 85239 piston part numbers -- using the same crankcase assembly which would obviously include the cylinder. That doesn't seem correct considering the dramatic differences between the two pistons. It only seems logical that the corresponding cylinders would also have different porting..., at least to me. Maybe not? I'm guessing the 85240 was the predominant 6-10 6-10A piston simply because of the production history and the subsequent introduction of the 7-10.

It certainly seems as though the 85239 number supersedes the 69030 piston number for the windowed design and applies to both thin and wide ring versions (as both ring sets are listed for the same piston part number) and the 85240 number supersedes the 69412 piston number with the full skirt and more closed design and was only a thick ring piston according to the associated 87166 ring set listed. I couldn't find any reference to the 69412 being used in a 7-10.

Unfortunately, this rather self-indulgent exercise in IPL research/exploration doesn't shed any new light on Kevin's 7-10 mystery and only proves once again that you can never be sure what's inside a Mac even when you know what you're looking at!

As for the accuracy of the illustrations, they at least attempted to show both styles of pistons in their respective applications. But we know all too well that the same illustrations were generally applied to multiple IPL's and similar models, particularly over the course of the 10 series publications. So when in doubt, double check the part number and hope Google is your friend in providing decent and accurate pictures of what you're trying to identify -- which, by the way, is how I came to my general conclusions with the part numbers at hand. Pretty amazing how many of Mark's posts pop up when you're researching this stuff! 7-10 / 6-10 Pistons

Just wish I had more time to explore the IPL's. Don't you guys? LOL

Sorry again, fellas. And good luck, Mark.

 

[sawfun]

Either one of you ever ran a SP125C? That's big power and surprisingly very manageable power. Not a hard to handle beast that one would think. Very easy saw to run but will break you down to carry.

Brian

A 125 is so much nicer on the operator than an 088, way more low end, usable power too.

 

[Brian Thacker]

Yeah I agree.



a 125 would be rather nice. I imagine it's a bit like a cr500 really nice fat smooth power and can really be nice and manageable up hills n stuff or lugging around behind the kids. Not really the savage beasts there made out to be. A cr125 will throw you off the back up a hill far easier as you need to keep it singing lose momentum and your fighting the front wheel or out of the power and stopped

I wished I still had my CR500. Such a wonderful bike, I miss it dearly. And yes like a CR500 and you are right, much difference than a CR125, not hyper. Smooth power from bottom to top. Kind of like my old Husky WR430, Just power everywhere.

Brian

 

[PogoInTheWoods]

Sorry to intrude on this all important discussion,but does anyone know what the bar mount pattern is on a 380A?I've been told that I can sub out a modified Husky bar,but which one of those do I use.Tim was kind enough to come by after the GTG & help me out with a couple of saws,the 380A being one of them.I'm very close to it being a runner now,just gotta rebuild the flatback yet.
Ed

A D009 large mount Husky bar can be fitted to the 10 series saws but I don't think they fly on the larger frame mounts. Here's a great write-up that addresses the issues. Didn't realize the bar plates were so complicated to sort out but sure could explain any number of possible oiling problems with larger frame Macs.

http://chainsawrepair.createaforum.com/mcculloch/large-frame-mcculloch-bar-mounts/

 

[Jethro 2t sniffer]

hmmm somebodys thinking dirt bikes

Sent from my VS995 using Tapatalk

Love them but don't have any now

I wished I still had my CR500. Such a wonderful bike, I miss it dearly. And yes like a CR500 and you are right, much difference than a CR125, not hyper. Smooth power from bottom to top. Kind of like my old Husky WR430, Just power everywhere.

Brian

Really really nice bikes my uncle has a 94 and he's gone to the trouble of getting it road legal and what a blast it is on the gravel roads and stuff here in nz just the gas tank is a bit small

 

[2broke2ride]

I appreciate all the input from everyone trying to help out with the 7-10 and I want to thank Mark especially for putting in the time.

 

[sawfun]

I wished I still had my CR500. Such a wonderful bike, I miss it dearly. And yes like a CR500 and you are right, much difference than a CR125, not hyper. Smooth power from bottom to top. Kind of like my old Husky WR430, Just power everywhere.

Brian

I had an SC500 and a CR500 as well. Four stroke torque at lower rpm and two stroke power up top, the best of both worlds.

 

[heimannm]

I am not sure where to go next Kevin - I have run out of option...

Mark

 

[Jethro 2t sniffer]

I am not sure where to go next Kevin - I have run out of option...

Mark

Mark have you measured the bore by any chance?

 

[Brian Thacker]

I had an SC500 and a CR500 as well. Four stroke torque at lower rpm and two stroke power up top, the best of both worlds.

Yes. I also miss my old 501 and 400 Husaberg

Brian

 

[2broke2ride]

I am not sure where to go next Kevin - I have run out of option...

Mark

I fell like we have covered most bases. It seems stupid but what about the kill switch? I've had kill switches cause some really weird problems on snowmobiles.
I was also wondering if there is a way the engine could be pulling fuel into the intake through a pinhole or crack in the intake tract. Seems like a long shot but I'm grasping at straws. When I was messing with it it seemed really rich at low speed, exhaust was noxious and I had to ha e the low screw turned way in to get any kind of idle at all.
The only other things I can think of are either a bent rod or, as you suggested, the wrong piston.
You tried different carbs, different ignitions, and we are sure the motor is sealed.
Is a twisted crank a possibility? Again I've seen it on bike engines but seems like a long shot on a saw.

 

[PogoInTheWoods]

I had to ha e the low screw turned way in to get any kind of idle at all.

I believe you mentioned changing the trigger? Any chance there's something weird going on with the throttle linkage after the trigger change that's creating all the futility at the carburetor end? Or maybe something related to the kill wire/switch when the linkage is in the idle position?

 

[2broke2ride]

Unfortunately Tim, I dont think it's going to be something that simple at this point. At any rate, I would think, if anything, the wrong trigger would tend to cause a too high idle condition.

 

[Maintenance supervisor]

Unfortunately Tim, I dont think it's going to be something that simple at this point. At any rate, I would think, if anything, the wrong trigger would tend to cause a too high idle condition.

Could it be a casting defect in the impulse port? I don't know ports or passages but if you could sleeve it with copper tube or epoxy it full and redrill it that would solve that. ???

 

[fossil]

A D009 large mount Husky bar can be fitted to the 10 series saws but I don't think they fly on the larger frame mounts. Here's a great write-up that addresses the issues. Didn't realize the bar plates were so complicated to sort out but sure could explain any number of possible oiling problems with larger frame Macs.

http://chainsawrepair.createaforum.com/mcculloch/large-frame-mcculloch-bar-mounts/

Worked well for me on the CP125. I just filed the adjust holes until they entered the bar groove and away it went. No chain dragging or any other issues.

I did fix up a 24" D009 bar by sort of turning it into a D096 + two new chain adjust holes for the SP80. Works well on larger Pioneer P series, MAC 10 series and the Homelites and Poulans that will take a D096 or Windsor UXL mount. I haven't tried it on my MAC 380 to see how it covers things without bar plates.

D009's can be pretty versatile if you have a drill and a file. No reason Stihl bars couldn't be as well with some spacers.

 

[heimannm]

Kevin's 7-10 was a running saw before "we" acquired it as it had a lot of hours on it when it came to me. That's not to say there isn't a problem with the impulse passage but I have done my best to confirm everything is copacetic.

Mark

 

[Jethro 2t sniffer]

Worked well for me on the CP125. I just filed the adjust holes until they entered the bar groove and away it went. No chain dragging or any other issues.

I did fix up a 24" D009 bar by sort of turning it into a D096 + two new chain adjust holes for the SP80. Works well on larger Pioneer P series, MAC 10 series and the Homelites and Poulans that will take a D096 or Windsor UXL mount. I haven't tried it on my MAC 380 to see how it covers things without bar plates.

D009's can be pretty versatile if you have a drill and a file. No reason Stihl bars couldn't be as well with some spacers.

I run a D009 on my 800 very easy just filed the holes oval towards the stud slot until the adjuster would fit and cut the oil hole through into the bar groove with a dremel a S clip oh and I tig welded up the old oil hole too but maybe that wasn't necessary but the bar plate didn't quite cover it up. It is a lot wider in the tail compared to the proper old mac bars so maybe it would be fine on a large frame too. The mac bars are too narrow for my poulan 4000 too.

Vinny runs a few stihl bars on his macs and Ron does also