2006 yz250f jetting or air screw trouble?

got an 06 yz250f. it used to run perfect, start on 1st kick, be very responsive, and it would also idle perfectly cold or warm. i laid it over cracked my stock header, so i bought another stock header and muffler off of an 09 yz250f and have recently put a boyseen quickshot on the carb. ever since i cracked the stock header pipe and ruined my bike really hasnt ran the same so im taking a guess its jetting and/or air screw so can somebody please tell me what kind of jets and what position my air screw should be in for the 09 header and muffler? thanks for your time and any ideas or help would be great.

It is not an air screw on a 4S, it is a fuel screw. It is for idle only.

You obvioulsy had a hard crash, to off cracked a stainless steel header. But your description of the running problem is terrible vauge. I can tell you, jetting does not change on its' own, something else either happened in the crash or you 'fixed' something to induce the problem.

The difference between a 06 and an 09 YZ exhaust is insignificant and will not affect jetting.

Were you running the Quickshot before you damaged the header and replaced it?

yeah the quickshot was put on about a month before the wreck, i really didnt fall that hard when i wrecked either so i know the wreck didnt cause anythig else to break.

You need to better explain the running issues you are having.

When you replaced the exhaust did you install new exhaust gaskets, or reuse the old ones? You definately aren't giving us much to go on. What are the symptoms specifically?

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