WR400 with erratic idling

Recently have problems with the bike idling. The idle speed is irregular and goes slow,fast,slow fast and then sometimes dies off. Havent had this problem before. My guess is this was caused by water in the air box a few days back. Carb and air filter cleaned thoroughly but its still the same. Any idea what the irregular idle speed suggests and if water causes this kinda problem? While moving i dont experience any problems its just the idling. :thumbsup:

If you all of a sudden have hanging revs which then drop when you blip the throttle

Read the post on the link below.

If you have an old WR read the post anyway !!

Carb Slide Post

i am using an aluminium aftermarket slide so that is not the problem. Anyway i meant normal idling, the rpm goes up and goes down then up again and so on.. by itself :thumbsup:

What year is the bike?

Sounds like it may be an intake manifold leak. Check for crackes in the rubber and make sure the carb is pushed in all the way and the clamp is snug. Check the hoses from the airbox too. It seems to me that my bike acted up after I had the airbox off and there was a little nib of a hose that wasn't in place. I can't remember exactly which hose it was, but it was a short little nibbly thing.

its a 98 model

would a loose spark plug cable to the plug cap cause tis kind of irrugular idle,

correct me if i am wrong, if i could see small sparks flying under the tank it would,


just thinking it might be the pilot what is lean.

juts my 0.2

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