I have a 99 wr400 and i retarded the exaust cam 1 tooth to be like the yz. It starts good and runs good but will cauf and die while idling, even when warm. I was wondering if there is anything i can do about it? Thanks.

I thought the wr400 was already retarded one tooth and you had to advance it one tooth to be the same as a yz400

^ incorrect.

The exhaust cam needs to be retarded to match yz spec. But with the heavy wr flywheel it still won't rev like one.

Pull your pilot jet and clean it.

Unscrew fuel screw clean it and re-seat at 1+1/2 turns from bottom.

Also make sure PAJ isn't blocked.

How did you go with it? I'm rebuilding mine and have changed the timing to yz timing but haven't tried it out yet. Did you re-jet the carby?

clockwise, I didn't rejet. Cam timing was all i changed. I will check the pilot but it idled fine before.

Ok well keep us posted on how it goes for you:)

was wondering if you figured out the problem. I have the exact same issue. 99wr that starts ok but soon as I touch the throttle it coughs and dies.

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