OK, I'll admit this isn't the prettiest work around, but the cylinder wasn't very nice to begin with and I didn't care a whole lot, it was a proof-of-concept job on my L65, Bottom fed, closed single transfer converted to a bottom and piston fed semi closed transfer design. Yes, I lost base compression with all that I removed, and it does show in the bottom end grunt of the saw, but the top end gains were very good.
I had previously ported the saw with a bit excessive timing numbers, close to 90/118/90, and it ran like CRAP... there was a ton of intake reversion, and it would bog badly at anything under 8000.. it was unworkable... I think anyone would agree that these saws have pretty lousy transfer ports, so I figured if I could improve the flow there, it may come back to at least a tunable state if the transfer port flow improved, thus emptying out the crankcase better, which would in turn lead to higher intake velocities and less reversion.
This is a stock (left) and ported (right) version of the same cylinder... but I didn't change the basic design of the transfer at all
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Here is a side view of my modification, showing what I cut out
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And here is the windowed piston shown at BDC with the modification
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This really helped 'cover up' the excessive port timing.. it does have a narrower powerband than a saw with 'standard' numbers, but it's still a whole 'nother animal compared to the saw in stock form. Also, because of the high exhaust port, the saw only has about 140 PSI compression, but I'm happy with it now. if I had as much foresight as hindsight, I'd have taken .020" off the base while I was still able to chuck it on the lathe, but with the skirt mostly gone, I can't do that anymore with the tooling I have.
Here's the saw with a 24" bar in dry fir... I think it's OK for saw that's usually considered a slug at best
The long and the short of it, is I could have left my 'mistake' cylinder alone, tossed it in the garbage, and never learned anything... Instead I took a chance and spent a few hours and got a saw I enjoy running once again.