Hey guys I am at sea level and have 2006 yz450f with a 52 pilot and 170 main. Has terrible popping on decel until I get the mix screw out to about 3 1/2 - 4 turns then runs great. But the screw fell out from the vibration. So it Seems like I need a bigger pilot but a 52 is already bigger then what anyone is using on what I think is a stock bike, that I've talked to. Could anyone please tell me if this seems right or could it be something else?

At sea level, you should be running a 45/168. You either have an air leak in the exhaust system, or your current pilot jet or the pilot circuit in the carb is partly clogged.

I'm at sea level with an 06 aswell . I'm running 48/170 and I need to go to a 45 as I'm usually around one or less out on the fuel screw. You must something going on.

Is your bike hard to start when warm ? Do you need to use the hot start ?

I just had the carb rebuilt and i put a 48/170 in it. It was popping really bad so that's when I put the 52 in it. I also just replaced the header pipe and the exhaust gaskets. Also it starts easy even when hot.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now