I'm curious, how does a piston change equate a 5hp difference in power?
the 250 is what, 16hp or so at the crank (and I'd say I'm being generous considering what the trx300 puts out)? so a piston is supposed to give you an additional 33%
increase in power?
is the four valve head swap possible? that would see some power....
I also say the 386 kit I suggested would crunch the sx gear box... I've seen it crunch the 300s and the trikes are likely built lighter