yz timing for my wr?

I'm looking for directions on setting the timing on my WR400F to the YZ400F specs.

Also, I need suggestions on how to re-jet the carb.

Just had my suspension re-worked by Devol. It's sweeeeeeeet.... Now I'm ready for some timing/jetting mods.


There is a ton of help to be had here at TT. As a matter of fact you were just razzed :) by one of the best (mx tuner).

Provide some info on what mods have been done to your bike such as air box lid removed, aftermarket pipe and ambient info such as altitude and temps.

Let us know and someone will jump in.

Welcome :D


No worries. I had to laugh after MX's reply.

Once I change the exhaust timing to the YZ specs, and set the main needle down a notch, I plan on riding it for a while.

Once I find a pipe, which out of 8 jets listed in my owners shop manual would I need to purchase, and what sizes? Is there a set "formula" included with the exhaust pipe or from a carb tuning spec sheet, so I can dial it in the first time, and not have to tear into the carb more than once or twice?



99WR400f, grey wire cut, Devol revalved/sprung suspension, Michelin M12 F/R, stock exhaust without the cork, airbox lid mod, renthal bars, Gutz seat.

Retard the exhaust cam one tooth to get YZ timing. There should be 12 cam chain link pins between the timing marks at the 12:00 position.

To rejet your carb, you simply take the little brass thingies out and put different ones in (sorry, I couldn't resist).

If you go with the yz timing you will want to go with a yz needle. I think the ELN (yz250f) needle is a good starting point.

It will make a huge difference.


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