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?