tuning yz426

[atvfreak400]

I have had my yz426 400ex away getting set up and Iam not happy with the way that it's running.It has a small bog if you hit it from a dead idle,if you keep the reves up it fine and it has alot of carbon in the exhaust and on the plug , and a little back fire on deceleation.It's about 48 here and I have a 45 pilot 165 main and the mixture scew out a tune and ahalf, I feel is if it is running rich and I should go to a 162 main or even a 160 as the temp is going up .what causes the backfire to rich or to lean?.Iam just learning this stuff so go eazy on me thanks

[bozz]

I would try two and half to three turns out on the mixture screw.my yfz did that before i went to three turns out and boysen quick shot acc pump cover.and 168 main ncvq needle

[atvfreak400]

I will try adjusting the air fuel screw. I had them put on a boysen pump on it at the sop when it was there but thanks for the help.