jeting

[89250rhonda]

hi, nead some jeting help i have a 86r with trx-5 pipe, .80 over bore and brand new KEIHIN 38mm pwk carb, high compreshion, running u.k pump gas.
i have all ready melted a piston as i was to lean
thanks.

[89250rhonda]

and 0-100ft, 40-60 degreas

Very similar to another jetting question on this forum:

First what is your current jetting set at and what is high compression; how many PSI's?

Will assume that U.K. pump gas has an octane rating around 92, with a non ported cylinder and compression above 165 PSI and less than 190 PSI…

First make sure your carburetor is cleaned out, float level is set correctly, needle is shutting fuel off and the slide works smoothly.

I would start with 175/48 or even 182/50, needle clip 3rd-4th grove down from the top, air screw 2 turns out…

I am suggesting this set up purposely rich with a 38MM Keihin carburetor, I would like you to error on the rich side since you don't really know why you are lean and fried a piston...

I suggest a complete leak down test, looking for all possible air leaks everywhere…then jet, test ride and reject as needed.

Look at your plug & exhaust temperature and jet accordingly…

Carlos.