Posted: July 6th, 2009, 10:49 pm
i aint retired yet 
100hp honda wrote:i was always under the impression to gain any significant amount of topend power you have to increase the total exhaust window area, which hampers your low speed power......... hence the reason why manufacturers started using powervalves. let us know if you get that
"all over" power increase like you were promised
in my multiple stages of porting, I would make some changes, ride it, then make follow up changes based on the performance. it got to the point where the off idle hit was so strong I would just loop the thing everywhere
so I decided to move the power up in rpm by raising the exhaust. its actually the exhaust position that does it, not so much on the size, because I got that exhaust as big as it could go and only gained more down low. now that I'm running like 200* exhaust duration the hit moved up, probably a good 800-1000 rpm and the bike revs way better, but now it has next to nothing right off idle, then a sudden burst of power. in trying to make it more controlable, I actually made it a lot less controlable, but moving the power up did help it get to the top of the hill faster. 