Red,
I'm wondering about swept volume/trapped volume/chamber volume in a saw with this very long stroke.
What 4 Paws said speaks in volumes to me.
This saw should be much more sensitive to raising the exhaust than others. You probably knew this already. Any change will reduce trapped volume and overall combusted charge much more than what we are used to.
I'm wondering if this is a case where a combo popup and band cut may make the most sense. This is the only place that I hate short skirts.
Because of the long stroke, a degree of exhaust roof should be quite a bit of difference physically.
I'd take .015 off the piston edge to match the chamber as best I could. That's my idea without holding the jug and piston in my own hands. It may not be possible.
I see increasing compression more difficult with this geometry. Maybe a dab of 4340 via Tig in the chamber?
After Cobey's compression report I feel a lot better about being able to get compression up.
But yes that was my original thought process, factory kept the exhaust low and 150psi. Didn't think even cutting the base / squish would allow me to raise the exhaust to normal heights (103-105).
After talking with some others that have ported these, they have gotten good results going as high as 102...
Maybe on the next one I could cut the base and do a popup.
With just a gasket delete squish is still round .020, so some would have to come off the base. (.035) appears to be max am out before freeport.
So if I cut.030 off the base, leave the factory band, and .030 off of the piston. To get .020 squish.
Or split the difference? .015 out of the band and .015 off the piston?
I do not have enough skirt to make the squish band and or the piston band flat. Has at least .030 taper on the crown
Wonder if .005 or so freeport would really hurt this saw?
Going to see where the comp comes out on this saw, before I think about welding the chamber. But that is still an option.
