Thanks for the responses to my query. I think BRS's comment,
Quote:
|
Usualy the manufacturers make an engine case to be used by a variety of models. Same case different internals, its normal to see the liner not lining up perfectly with the cases, especialy on the exhaust side
|
is the most likely reason as to why the liner doesn't match the port. Maybe grinding the liner away could unleash hidden power but I don't think I'll bother 'cos of this prophetic warning
Quote:
If you want to have a play with it get your dremmel out but dont go crying to anyone if you fuck it up 
|
By the way, lowering the port's bottom edge won't affect the port timing. It will still open and close at the same time and therefore it's duration isn't affected. It will just be bigger. And, because the transfer ports are open at the same time as the exhaust port, lots of unburnt fuel passes straight through the engine into the exhaust. Good job someone invented the expansion exhaust system otherwise 2 strokes would lack a lot of thier power and be even more thirsty for fuel!