03 yz 250 Idle extremly high

[uhlanmc]

I am jetting my yz and I've only gone one size down on the pilot jet, and 2nd needle clip from the top. When I started the bike, the Idle was way up, and no matter what I did, the bike wouldn't come down. Top end? Compression was 150. I'm pretty sure this is the problem. thanx.

 

[Spine_Thrust]

Did you kick the bike over several times when testing the compression? Usually takes about 10 or so kicks to get it to its highest level.

Did it do this before the jet change?

Does the throttle slide move freely?

 

[AssistSuper]

Did you somehow mess up the idle adjustment screw?

 

[2-stroke diehard]

Also make sure your throttle adjustment screw is where it should be.

 

[DLHamblin]

I am jetting my yz and I've only gone one size down on the pilot jet, and 2nd needle clip from the top. When I started the bike, the Idle was way up, and no matter what I did, the bike wouldn't come down. Top end? Compression was 150. I'm pretty sure this is the problem. thanx.

Also make sure you don't have an air leak (not sure if you removed the carb to jet or just loosened and rotated). A small air leak can cause this as well.

 

[KDXman_88]

I have the opposite problem, mine wont idle. i think i just need to turn the idle screw up.