Possible rebuild ms880 magnum

[sportystv]

So bought a used ms880 off a friend. When I first started the saw it had a really loud strange noise coming from it. I changed clutch needle bearing and checked to see if recoil was getting caught on flywheel. Started it after and it didnt sound as loud but kinda still ran like *s-word wanted to die so turned it off. So I went ahead and compression tested it 3 or 4 pulls cold has 150 psi. Then I pulled muffler and seen that the piston has some scoring. Ordered new meteor piston. Well I pulled the jug off to take a look( im New to working on saws, brand new) and looks as it may clean up but for 1 spot that is not good. Would like to know what some of you experienced guys think. The chip on bottom of intake side is where I'm guessing where the problem started. Bore feels smooth on intake side. Wondering how saw still had 150psi compression. Thanks for the help.

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[sportystv]

Sorry didnt realized I posted this in wrong section. How do I move it over to the right place.

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[Canadian farm boy]

@Mastermind can you help this fella out and move his thread to the chainsaw section? Ok, Thanks, Bye

 

[Mastermind]

@Mastermind can you help this fella out and move his thread to the chainsaw section? Ok, Thanks, Bye

You're late !!!!!

 

[NPKenny]

You can smooth out and blend in the chip on the bottom of the intake side with a grinding stone, file, emery cloth, etc. Your cylinder will clean up just fine from the looks of it. (from @Mastermind )

You should determine where the slight scoring was coming from. For future reference, it is always preferred to check a chainsaw that has piston / cylinder scoring by performing a pressure and vacuum test to identify any areas that are allowing leaks into the sealed portion of the saw. This has to be done with the saw assemble and is easier prior to complete disassembly. But now that you are this far, you can check the impulse circuit, fuel line and filter, tank vent, and carb tuning to give some hints as to what caused it to fail. Crankcase seals are also a common spot, but a little more involved to inspect now that the saw is torn down. This scoring is so slight that it could be as simple as a lean tune on a series of long cuts.

Good luck! You started with a monster of a saw.

 

[mdavlee]

I’ve seen scored saws with 180 lbs of compression. That minor scuffing will clean up easily. I’d throw a new piston in it and smooth that chip with a diamond ball and sandpaper.

 

[smokey7]

If it's a high hour saw I would pull seals and flush out bearings and inspect. Seals are cheap and its a expensive saw.