Any Idea What This Is???

[Mastermind]

I did pull one apart with worn out cage.......swap the bearing from a broken crank and make a good usable unit from it. It's a good tool to have around.

 

[heimannm]

I have a three piece crankshaft from a McCulloch PM8200 that I suspect is tweaked, saw had a very bad vibration when running at high speeds. Scarr52 let go of it like it gave him an electric shock.

Where can I send this one to have one of you experts check it out..Scott, Randy, anyone?

Should I remove the piston or just send it as is?



There is one way to make a single firing cylinder engine almost perfectly balanced



Maybe that doesn't count as a single cylinder any more. They are remarkably smooth and rapid acceleration to boot.

Mark

 

[Mastermind]

I'm in over my head already Mark. Scott is the man to see my friend.

 

[Deleted member 83629]

i wish saws had a solid 1 piece crankshaft instead with just a standard rod and rod cap with needle rollers in cased in a brass bushing.

 

[jar944]

i wish saws had a solid 1 piece crankshaft instead with just a standard rod and rod cap with needle rollers in cased in a brass bushing.

That would make the cases larger and the saws heavier. Not to mention split cage needle bearings are rare.

Split cranks are easy to rebuild, the fact that you can't get rod kits is the issue.

 

[a. palmer jr.]

Bingo...

I was gonna say banana peeler.

 

[Marshy]

He could be refering to the actual weight of the crank halves. Different saws use different cranks. Some older 044 cranks are thinner then their newer counterparts. A 10 mm 044 crank is lighter than a 12mm unit, and not just because of the rod. A 346 and 350 husky have very similar cranks but a 350 the crank weights look identical where as the 346 has different size and I assume diff weight crank halves for clutch and flywheel side. 064 and early 066 cranks are the same part number but I have seen a large variation in counterweight style, width, rod design etc depending on production date and application.

I think you about hit it on the head. Just consider the possible variation in actual counterweight weight within a single model or part number. Not necessarily just across different models but within the same part number. If you were going to separate two cranks and make one out of it (i.e. one of them had a good clutch side and the other had a good mag side) then you might find enough variation from the manufacture to throw off the balanced range. This was more of a questions than a statement when I started, not a statement of fact...

 

[jar944]

You don't need anything special to check the balance of a crank, and you can do each web independently (on a 3pc) with a bit more effort

single web

assembly

 

[RiverRat2]

Isn't this fun????