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WelL yes it'S little ol me again i have fitted up a Mac 101 i bought from a guy in LA to my twin 101 powered hotsaw but the problem is or might be a storm in a teacup not sure really ?
This 101 on arrival at my workshop had a repaired crank with the repair hidden under the sprocket some-one had rewelded the crank and ground it up and refitted the sprocket so imagine my disappointment when i went to remove the clutch or sprocket retaining nut and got more than i bargained for.

Anyway the rest of the engine is just fine it's stock and the piston has done no work it looks like new, so i fitted the counterbalanced crank from an SP125C these go straight in but now the problem since this crank is fitted with counterweights is there an aftermarket stuffer that will fill the void as the 101B stuffer doesn't clear the crank of the SP125C.

Mc Bob

Hey Bob, that sounds similar to what happens when you put a full circle, stroker crank, Big-J rod etc. in an Mc-101 or a WB-820. One simple solution I've seen is a stuffer spacer made out of sheet aluminum and two gaskets or sometimes just two thick stuffer gaskets. My engine builder could never do anything that crude, he fully machines a GEM Super Stuffer to just clear and be perfectly on center with the oversize crankshaft counterweights, but a spacer will work just fine for the most part unless you're concerned with losing just that last little bit of crankcase stuffing.
Those SP-125 powerheads really have a lousy low compression combustion chamber and like an Mc-70 there isn't much you can do about it. Stay with the 101s, Tom

Thanks Tom

Man we can't go on meeting like this the fellas will start talking about us, yes i'm staying with 101's but i have quite a few spare SP125C cranks curtosy of my mate who passed away a few years ago and left me a lot of his Mc stuff and i didn't have a spare 101 crank anyway.
I would imagine that the SP125C crank with it larger counterweights occupies a bit more room than a standard 101 crank and yes i'm in the process of making a couple of spacers for between the stuffer plate and the crankcase.
I have a few different standard stuffers to try so maybe one of these will be the magic bullet i'm after.

Mc Bob.