I have a 39pwk carb, hpd pipe, k&n filter. I was running a 170 main my plug was always brown but when i pulled my piston out today it was partialy melted in one area it was definitely running lean (can anyone explain this) I am going to put in a wiseco piston reed spacer and a clamp on filter. What jetting do you think I should run now? any help would be appreciated

 

Was your oil mixture OK? Many bikes have been ruined by faulty injector pumps or little or not mixing your fuel/oil properly. As far as re-jetting goes try it and check the plug that is the only way I know of getting it right.

 

i was running polaris synthetic at 40:1 with premium

 

anyone else?

 

will someone please help

 

Is it the race pipe or trail pipe ?Which needle are you running ?Have you checked your jetting at 1/4,1/2,wide open ?Which plug do you run ?

 

Like CED suggested, check your jetting. I had to massage the needle on my 39. You might check with HPD and see, I know at one time they were looking into some custom tapered needles. Take your time when doing the jetting runs, it will pay off with a better running machine.