Having removed my exhaust I notice that the piston crown at BDC is slightly above the lower edge of the exhaust port on my NOI engine. Is this normal or would a thicker base gasket raising the cylinder (albeit with a resultant reduction in compression ratio) be beneficial?
Do Garellis have dykes rings? If not, then you can probably dremel away some of the piston crown. BE CAREFUL when doing that, you don't want a hole in your shit.
Hmm, I think I'd prefer fitting a slightly thicker base gasket.
no dyke rings, but rather 2 FG. a slightly lower window shouldn't be a problem, but if it bugs you, you totally have enough piston there to shave a little off. The trick is making sure the the crown doesn't fall below the edge of the window, as you then have an obstruction. trading compression for a small increase in port time doesn't sound constructive, at least not as much as piston work.
Better yet, add a thicker base gasket, and shave the cylinder head down to bring your compression back up
Garelli has a funny way of head mounting, by the time you remove enough material to see any gain, your piston is hitting.
Can we mill out some?
I'll leave it as is for now, I reckon, but getting to 40mph (or even above 32mph) is turning into more of a challenge than expected.
I've had a fair amount of success with modifying piston domes. You want to leave a decent amount of metal above the ring for heat transfer. Bringing the rings closer to the combustion, especially on the exhaust side can lead to problems.
Jonathan
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