Ive got an 11:1 wiseco std bore, stage 1 hc, full ct, no airbox and k&n proflow with outerwear. I'm running about 175/180 with 27.5 needles (mikuni). I know that I will need to replace my headpipe or full pipe altogether to upgrade my carbs. What I am trying to figure out is what to upgrade to. Eventually I will be building the bike up more. Possibly even send it out so I dont have to keep getting my hands dirty. I know that since the stock carbs seem to have flow probs over 180 or so, I will need more fuel. I was looking at a set of 35mm Fcr carbs. The question I have is about the 39mm FCR's. Could I run something that big on my current setup? Could they be run on a mild to hi po 686? I just think that if I'm going to upgrade, why not get the best I can? I confess I dont know how much the 39's are, so any input on that would be great as well.

 

Is your head ported?

 

Its going to be by the end of the month, local shop.