if you put a reed engine piston in a piston port engine?

 

absolutely nothing....[img]i/expressions/face-icon-small-wink.gif[/img]

 

why not???? wouldn't it let more air into the crankcase?

 

It has to do with intake port timing. If you use a piston that doesnt close off the intake ports before the transfers start opening, then you get a lot of blowback throught the carb and they dont run well at all. Sometimes not at all.