My 98 WR400F was running like a charm until it POURED while trailoring it to a track...water in filter...fouled plug. ever since i have had nothing but problems...i drained the carb and put new gas in it...still not corrected. i get a lot of popping while starting it and when i let off the gas. it wont idle either, it just quits. any ideas at all will be much appreciated as we are leaving north tommarow on a ride. thank you.


sounds like water in the fuel/intake system...maybe you need to run it for a while so that stuff gets pushed through, and check your plug for fouling as well...? :thumbsup: As if I know anything...

another thought: after working on the carb, did you make sure it's venting properly? My KTM exhibited those very same symptoms until I figured out I'd pinched a carb vent tube after I'd removed all the emissions & secondary air system crap they had on there. Removed the kink and she ran like a champ...

It almost sounds like a lean pilot circuit now. Maybe the water washed some dirt out of the airbox into the carb and it clogged some jets or something. I know its unlikely, but it could happen.

Clean and blow out all of the jets. Make sure your fuel screw is adjusted properly.

Also make sure you tightened the boots on the carb if you took them loose. Heck, check them to make sure they're tight even if you didn't take them loose. That's a sure-fire way to make the bike really lean.

...also clean the hot start assy and all the small black tubes including the small membrane, everything on the left carb side and of course make sure that you re not riding with the hot start button pulled out

Make sur ethat you also give the Accelerator pump a very good clean... chances are that that is filled up with mud too... I had the same thing ahppen to me once, blew all the jets and pipe with the air hose, but was only better after servicing the Acc. Pump.

Now I run with the top part of the Acc Pump diaphragm filled with grease...

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