UK 04 WR450 stalls when revs drop to idle

[tikkar]

This bikes been parked up for 3yrs, (200miles only) & is ridden nr sea level, there's a grey wire but no AIS. It picks up from tick-over to full throttle ok, doesn't race before stalling or stall when being ridden. It's not allergic to deep water, but there's the usual slight back-fire on over-run & there's no plug fouling. It's got the usual horrible round stainless OEM UK can also.

Jets; 48 PILOT, 65 STARTER and 160 MAIN. It usually stalls when I slow down and pull the clutch, or just before trying to jump over a log.

The only thing I can find is the tiny ball bearing in the accel pump is stuck down, the "HAYNES" book says it should move free, if it is this ball anyone got any ideas how to get it to move without my hammer?

I've used carb cleaner on everything in the carb, but it was clean anyway & the only other problems with it are the hopeless leccy boot and it blew the comp plug over the garden when I first started it. Help!!!

[grayracer513]

It usually stalls when I slow down and pull the clutch, or just before trying to jump over a log.

Sounds like the symptoms of a rich idle. Find the source of the excessive richness and correct it.

The only thing I can find is the tiny ball bearing in the accel pump is stuck down,...

There are two such check valves in the accelerator pump; one for in, one for out. If they get stuck, it will generally only affect the accelerator pump. Do what you can to free it up.

it blew the comp plug over the garden when I first started it. Help!!!

That sounds like an obstructed breather hose.

[tikkar]

I got the little ball in the acc pump freed up with a staple and checked the breather hoses, apart from a dead spider, they are clear. (The new decomp plugs held in with a alloy bracket and a M6 bolt) The thing's been a bit better today with less stalling, but I've been riding on fast wet trails not tight woods so it's maybe just been getting less chances to stall.

The backfire is the next one to sort out, it's getting annoying, oh, and the starting problem was the battery, it's sh****d.

[04WR450man]

Have you tried tweeking the fuel screw? Also, I would recommend a JD jet kit, they run lean as shit standard.

Trev.

[gnarler65]

This bikes been parked up for 3yrs, (200miles only) & is ridden nr sea level, there's a grey wire but no AIS. It picks up from tick-over to full throttle ok, doesn't race before stalling or stall when being ridden. It's not allergic to deep water, but there's the usual slight back-fire on over-run & there's no plug fouling. It's got the usual horrible round stainless OEM UK can also.

Jets; 48 PILOT, 65 STARTER and 160 MAIN. It usually stalls when I slow down and pull the clutch, or just before trying to jump over a log.

The only thing I can find is the tiny ball bearing in the accel pump is stuck down, the "HAYNES" book says it should move free, if it is this ball anyone got any ideas how to get it to move without my hammer?

I've used carb cleaner on everything in the carb, but it was clean anyway & the only other problems with it are the hopeless leccy boot and it blew the comp plug over the garden when I first started it. Help!!!

Look for the fuel screw & try 3/4 to 2 turns out.