I have noticed most slip on exhausts for the Raptor provide a little more low end as compared to the full systems. I have removed my airbox lid & rejetted the carb & was considering a full exhaust over a slip on. I was wondering if anybody thinks installing a high comp piston(std bore) would equal/improve the low end on a full exhaust system compared to a slip on?

 

a high compression piston will give you a bit more low end, but dont expect too much just from the piston alone, it works better when combined with a cam, and best with piston,cam, valve springs, polish and port. I added the header pipe to my system after the slip on, I didnt notice much my riding partner who did the same thing swears it made a big difference at least to him riding in my dust (lol)