06 yz250f running lean

I Just put a pro circuit t-4 silencer on my bike and I took it for a ride with the stock jetting, on the high rpms it seemed to break up so I went from a 178 main jet to a 180 and the problem seemed to go away. So I pulled the plug after riding it for 15 minutes and it was whitish-grey so i'm thinking its running lean and it has very little popping when I let off the gas from wide open. I think its running lean on the pilot jet, pro circuits website says to run a 45 pilot jet and a 65 leak jet. Thats the jetting specs for the 06 which I have but I have a 07 system on it. For the 07 it says to run a 42 pilot jet and a 60 leak jet. Do you think that the leak jet and pilot jets just need to be changed??? And pro circuits website says to have the fuel screw at 2 turns out which I have done.



No offence here, but you have an 06 bike, go with 06 specs. All you have is the 07 pipe, it doesn't change the bike to 07.

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