still serious confusion with a 98 WR400

I went through all the carberator and there is nothing there. It's really annoying. Another fun fact I found out today is that the owner of the motorcycle went through trying to change the exhaust timing to the YZ's settings to give more power but the smart guy went back a tooth instead of forward a tooth. That could cause the valve o get bent but the motor cycle still runs on choke but when the choke is shut off it stalls right out.

If you need more info look at the topic I first placed Serious confusion with a 98 WR400.


What PJ is in the bike and how many turns on the Fuel Screw?

The 'choke' on the WR actually 'adds' fuel, - Clark is this correct? You may be way lean on the FS w/o the choke, but able to run with the choke engaged. Just an idea.

It sounds like there have been some performance mods done the bike - removed air box lid, removed exhaust baffle. The carb may be way too lean for the mods & weather conditions.

My '99 would not start w/stock 45 PJ after I removed the air box lid. I backed out the FS a 1/4 turn at a time and it would start/run better & better the more turns out. Once I put in the 48 PJ it would actuall start & run.


I agree with Brian. Furthermore, the choke add a fixed quantity of gaz independently of the throttle opening. Then the bike run leaner as you open the throttle since you add more air but not enough more fuel.

I had the same problem with an old gs400, was just dirt in all the carb. Look at the jetting, you should see the jet's number on the jets and post the datas, it could answer some questions.

Thank for the info (Brian) on the pj without air cover, my mechanic had some problem to find the problem, this will be a good clue for him.


Any luck with this bike?


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