the kmx is restricted in the exhaust front pipe with a washer and in the standard tailcan, buy aftermarket, more importantly the kips does not open fully at high revs, there is no way to make the kips work better at lower rpms, its already doing that well. If your engine no. starts with an A its full power, with a B its restricted. Its the thickness of a washer and the strength of a spring i beleive that stops the kips openeing fully at top end, luckily?!? when i blew my A engine the kips was undamaged, put that on B engine, full power. No idea about the carb, as i had one from an A, cant find the manual to check the jets.