Stalls at low revs - new problem

I've got an 08 WR450 with about 9000ks on the clock. Been bulletproof, however over the past three months it's developed a problem where it stalls frequently at low revs - just above or at idle when applying throttle. You go to accelerate and it just cuts out.

I've raised the idle, but it still does it.

I've done some searching around here and common advice is fuel screw. However, why would it have run perfectly for over a year and over 8000 or so ks, and just now develop this problem? Could it be a symptom of something else.

your needle may be starting to wear out?

Check the AP and leak jet passages. Are you getting a shot of fuel as you turn the thottle?

I'd check the valve clearances first, and clean the carb. Replace the spark plug if it's got any time on it, and ensure good fuel and a clean air filter. Symptoms could be a combined effort of causes, all adding up to your current condition.

This may seem too simple, but it's amazing what just taking the carb apart and zapping it with carb spray through all the jets and cavities will do. My 650R went from a snarling, puking, coughing pig (well, it was a pig no matter how you look at it), to absolutely purring like a kitty cat with nice steady idle. Too bad the carb on the WR is not as easy to remove. :thumbsup:

Thanks guys. I actually took it to a mate who was the former workshop manager at our local Yamaha dealer, and he traced it to a warn needle. New needle - no dramas now after one ride. Unless he cleaned it at the same time and that's fixed it.

Gasgaspilot - you were right! Should have tried it to begin with!

I was also having intermittent problems with the throttle sticking but didn't mention it in here as thought it wouldn't be related to stalling. He said that was also probably caused by the worn needle.

First time I've had the bike worked on by someone else since I've had it. Feel like I've betrayed the thing! Now knowing it was just a case of replacing the needle I could have done it in five minutes!!!

Thanks again.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now