jd jetting on yfz450 james

i live in illinois low alt i have gytr full exhaust no other mods and lid removed, i installed your kit th blue needle on third clip 170 main 45 pilot fuel screw 2 turns out i rode it today it ran great no hesitation, 15 minutes into riding it it would sputter at mid to top range, checked the plug and it seems to be lean (white), my question is what do i need to do to get it just right do i need to go up or down a clip or out with the screw a little or main jets, i just need pointed in right direction other than that the best gain in power ive had, big difference thanks for the help, chris its gotta be close it ran so good and i let it warm up before riding hard it was rode warm 15-25 minuted before stuttreing occured

Switch to the red marked needle in the 4th from top positon with a #168 main jet (included in the kit).

The stutter is most likely a rich condition when the YFZ gets hot.

Sorry I didn't get to your message earlier.


if its getting rich wont i have color on my plug ? before i got your message i put it on 4th clip with blu needle cause it says in directions low alt. use blue b ut anyway im getting a little color on my plug i am going to try your setting but i have a racr this weekend and i want to be on top, and i dont want to fry my motor by being lean , please help me with the info you have thanks

The red marked needle is still richer than your stock jetting, so it's safer in that regards. A sputter at low speeds is going to be from rich symptoms, not lean.


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