About to shoot my 400

Alright guys, help is despertly needed. I have a 99 400. today I went for a ride. The bike would not idle, for some reason. The bike lost all of its power, it felt like I was riding a little 60. I had to clutch it to even get going in first.The bike came alive alittle bit. with full throttle. I have not had a chance to check the plug. would a fouled plug give me these results. I would of thought the plug would of cleaned up after a while of riding if it was the case.


Of course nobody could tell you how to go fix your bike after one post... But here are some quick things to check before you take your bike to the dealer and go broke...

1) Check your plug, doubtful if a fouled plug would make your bike run like that, but just looking at the plug could tell you if something is wrong. If it is soaked with fuel your float in your carb might be stuck. If it is white and dry, this means you are not getting enough fuel.

2) check your air cleaner, I have seen bikes run like total sh#t because the owner did not clean the air cleaner enough.

3) Clean your carb VERY thougouly. Run string through all the jets to ensure there is nothing clogged in them, look inside when you twist the throttle, there should be a pretty good stream of fuel squirting out when you twist.

4) work your compression release back and forth, look down at the engine and push back and forth with the lever squeeze. If your exaust valve is sticking open you will have no or little compression, hence no power.

5) if all else looks fine, it sounds like it may be time to do a top end job (piston, rings)

Hope this helps, the manual should help you through anything you get hung up on. If you truley do not feel up to it, leave it alone and take it to someone you trust. Good luck


Tim, I checked the compression release it was fine, the spark plug was fine,a little rich but that was how it has always been. The filter is as clean as is could ever be. The bike ran fine up and down my street a couple of days before. Tommorow I was going to rip the carb a part just to make sure everything is fine in there. It seems like the compression is fine but I will try and do a leak down test on it A.S.A.P so any more info you might be able to give you be greatful thanks

I remember once when I was living in Ga and some dirt dobers (wasp) had made a nest in the exhaust and the cr80 would barely run, so you might want to check your exhaust for obstructions. I don't think it will be it but you never know.


99YZ400F (him)

00TTR125 (her)

You might try checking to see that the clip didn't come off of the needle. That would result in very poor running/no power.

sounds like your APJ. the accelerator pump jet. undo tthe clip twixt carb & airbox, crush the airbox behind frame tube, open throttle & look for a stream of juice from a litttle post that stands 4mm proud of the bottom of the carb venturi.


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