05 Yz 250f Carb jets

If I am looking at the bottom of the carb with the bowl removed I can see the main jet and two other jets. I need help identifying which is the pilot and what is the third jet?

The service manual contradicts b/c one diagram shows the pilot jet nearest the air/fuel mix screw and another shows it on the opposite side of the main jet. The mysterious third jet is a #72. Main jet is 188 and what I think is the pilot has #45. So my question is what is that #72 jet?

Pilot jet has a slot for a flat head screwdriver and is about 3/4" long. The really small one, the #72, is the leak jet.

The #45 jet recessed in the 'tube' near the fuel screw is the pilot (slow fuel) jet. Center is the #188 (kind of large) main, the #72 jet is the starter jet.



The leak jet is in the bottom of the float bowl.

Thanks guys it was the starter jet I was wondering about. I didnt see anything in the manual about that and the parts schematics just call it a "jet".

This bike has a high comp piston, hot cams, and Yoshimura exhaust. Seems like it's still too lean so I'm going to try going up another size on the main or maybe move the needle a notch.. I guess I'll leave the starter jet alone for now.

a 188mj is WAY fat.


you have som ting wong


and a 45pj is kinda fat too.  are you riding on the ice already?

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