McCulloch Chain Saws

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Can someone tell me if the CP125 oil tank housing will fit the SP125 saw? Looking at the IPL they are different part numbers, just figured they might just fit.

Thanks,

Man they sure look the same. I guess if the arm that holds the front of the gas tank is the same, then the oil tank must be close enough that it doesn't matter.
 
I have noticed that some parts are pretty much the same but have a different p/ns. There is a lot of interchangeability in Mac parts, and it seems like sometimes they would use the same part but change the number for a new model. I would bet they are the same but couldnt say for sure.
 
They bolt to the block the same way, but have different A/V setups and the mount bosses on the bottom are different. I expect you can use either tank with either saw so long as you have the matching bottom bracket.
 
It may be red but it isn't all rosy on the 101B.

I bolted the new to me 101B to the bench, put a recoil starter on it and checked the compression - a consistant 62 psi. Changed gauge to an old one that always reads about 30 psi lower and sure enough all I could get was about 30 psi. Rings are free, piston and bore look good. I don't hear any leaks around the sparkplug hole. I have contacted the seller and I am waiting on his reply before I open it up. Any thoughts? Seller described the motor as: "McCulloch 101B that should be ready to run. Has a fresh bore and piston. Has been run on the bench, but no time on the track or road. No carbon build up on the piston. Head shroud is aluminum, and has cracks, but no dents. Could be fixed to show condition easily. Comes with the double pumper carb, super stuffer, and chain guard. Crank is keyless and has left hand threads that are in excellent shape. No disappointments." I am hopeful there is some simple to fix problem.

Ron

PS Many thanks to the one(s) who said to always leave on a loose flywheel nut when removing a flywheel. That baby popped and made me jump but it stayed nice and safe on the shaft.
 
I bolted the new to me 101B to the bench, put a recoil starter on it and checked the compression - a consistant 62 psi. Changed gauge to an old one that always reads about 30 psi lower and sure enough all I could get was about 30 psi. Rings are free, piston and bore look good. I don't hear any leaks around the sparkplug hole. I have contacted the seller and I am waiting on his reply before I open it up. Any thoughts? Seller described the motor as: "McCulloch 101B that should be ready to run. Has a fresh bore and piston. Has been run on the bench, but no time on the track or road. No carbon build up on the piston. Head shroud is aluminum, and has cracks, but no dents. Could be fixed to show condition easily. Comes with the double pumper carb, super stuffer, and chain guard. Crank is keyless and has left hand threads that are in excellent shape. No disappointments." I am hopeful there is some simple to fix problem.

Ron

PS Many thanks to the one(s) who said to always leave on a loose flywheel nut when removing a flywheel. That baby popped and made me jump but it stayed nice and safe on the shaft.

I would pull the engine down and measure the bore and piston. Something isn't matching up.
 
Thanks, guys. When I joined AS I never thought I would be going further than just putting in a carb kit and tuning it so my MAC would be easier start. Now I'm tearing into kart motors just to have a little hotrod saw to show off. I do get a little frustrated and tell myself to just buy a couple new saws and leave the old ones to you guys, but something keeps pulling me back, especially the thought that one day I could end up with an old saw that can't be fixed not because the motor is shot but because some molded plastic part has crumbled and a replacement isn't available. Ron
 
Been through enough shenanigans with 101s myself, hate to see you go through it. Ring end gap, bored over, but piston and rings don't match, dry bore, all could be a source. Oh, warped/badly milled head, head gasket leak???
 
Longshot, but....

I've got an NOS SP-81/PM850 piston and rings (in box). "C" application. Part #92520. Would like to trade it with someone for an "A" application piston assembly. Part # 92518. Piston and rings are new and basically perfect. Box is still intact. Mixup...:(

Not in a big hurry for it. I got an NOS SP-81/PM850 (that's the models that the McCulloch "cylinder kit" paperwork addressed) cylinder/piston "kit" to put aside for whenever I need to freshen up my SP-81 (or rebuild a dead saw if one comes my way). Somehow, the piston in the "kit" got switched with a "C" piston. My cylinder is an "A" cylinder (stamped next to the decomp valve port). Anybody here have an "A" (92518) piston for these saws?

Alternatively, does anyone here need a "C" piston (92520) for these saws and want to trade something else for it...........or maybe wanna buy it? Only one "A" piston on feebay right now, and it's bloody expensive. Same guy is also listing a "C" piston like mine for the same money....
 
i've got some SP81 rings out in the shop. i'll go check to see if there is a part number. by the way, what is the difference between "A" cylinder and "C" cylinder? and why would the rings be different?
 
i've got some SP81 rings out in the shop. i'll go check to see if there is a part number. by the way, what is the difference between "A" cylinder and "C" cylinder? and why would the rings be different?

I don't know exactly what the differences are, but McCulloch stated that there are three pistons and cylinders for these saws. Cylinders are marked "A", "B", or "C". Unmarked cylinders are the same as "B". The pistons have their own part numbers, and are also stamped "A", "B", or "C" on the underside of one wrist pin boss.

They stated that these pistons/cylinders are "matched sets", and must be used that way "for best performance". Once I figure out how to scan stuff, I'll scan the paperwork that came with my piston and cylinder. Spells it all out..............in four or so languages (including Japanese)!
 
i checked the rings that i have, i have never removed them from the package. the only problem is the package they came to me in, it only says SP81 on it. there is no part number. sorry about that
 
i checked the rings that i have, i have never removed them from the package. the only problem is the package they came to me in, it only says SP81 on it. there is no part number. sorry about that

No problem. Looking at my IPL's, it appears that the rings are all the same. Only one part number for the rings. Just the three part numbers for the A-B-C pistons, along with the notation to match them with the appropriate cylinder.
 
Hey Aaron did you get that starter yet?

Sorry Ted. Got it on Wednesday (was wating for me when I got home from work at 1230AM thurs). Looks great. That shield on the starter looks new. Thanks a bunch my friend. I plumb forgot to say anyting to you. How's the 795 coming along?
 
Oh that's okay Aaron. Yea that cover was right dirty, but with rust doctor fluid it cleaned right up. Rust doctor is great stuff, it is like soft soapy water on the hands and paint, but cuts right through even the toughest grime.
I have not fooled with it much after getting the other comp release sorted out. But to achieve full potential I think it will need a + piston/rings, the honing did not get the entire cylinder so I think the new rings just won't seal like they could. I'm sure the new rings can be applied to a future project if I do go with an overbore. so no sweat. I would rather get my 797 running with a 50'' roller nose attached. Waiting on a paycheck for now. .
 
I posted this over in the chainsaw forum, guess most of the youngsters haven't a clue how sweet these saws were (and still are)

It is a project I bought from the classifieds here. Repaired the bar studs and bottom handle mount. The muffler cover was pretty well shot and came sans a spike.

Found a little time to give the old girl some lovin' last week. Other than the aforementioned problems the saw runs great and has some serious compression, 70cc of good ole American power!

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