i picked up a motor out of a smaller chainsaw, i dont know how big it is,(prolly around 21-29cc). it has needle bearings on the con rod, two rings on the piston, some evidence of blow by(just a bit) but my real question is the intake port is on an angle, and i would like to smooth the passage. will cutting the carb BELOW the butterfly ruin the carb? maybe about 1/8 inch in some places. the exhaust port is next, it is only two holes the size of a pencil so i know that could be improved. it is a zama carb and apparently there is a passage from the diaphram chamber up to a port that leads out of the carb.... is this normal?

Needle bearings are BAD if they are on the crank shaft too ( some of the cheaper saws). They wont take side thrust. You want Ball bearings on the crank. Needles on the con rod are OK

they wont be getting any side thrust. so am i in the clear to cut beneath the butterfly??

Cutting the carb after the butterfly and after the ventui is OK.
But a bigger carb is easier.

yeah, but i dont think i will find a carb to fit the block without a real mod job, im just looking to smooth anyway. the bore is .725 inches, so i hope its big enough. tx for the info...

Before you fix something that broke, convert the engine and get it running correctly. Then play with things, that way you will know if the idea was a good one.