WR400 won't run after sitting awhile

[Heywood]

Hey all:

I have a 99WR400 with a Baja Dual Sport kit. It has been sitting a little while (a couple months) and when I went to start it, it starts fine with the choke on, bit turning off the choke it starts a popping and a sputtering and won't idle. With the choke on, runs ok with a high idle. The bike ran great before I parked it.

Sounds like an air leak, but haven't found anything yet. Well, actually there was a little rubber plug on the carb that was from the octopus removal mod and it was rotten and cracked. I though I had found it! I replaced the rubber plugs, but that was not it.

I replaced the gas, spark plug, pulled the carb and blew out all the jets, fresh air cleaner, and still no help...

I pulled the hot start off the carb and plugged the hole, no effect. The compression release operates normally.

Anyone have any ideas? Could it be something internal (stuck valve or something?). I haven't checked the ignition, could an ignition problem cause these symptoms?

Any help would be greatly appreciated.

[charliep]

I have 05 WR450. I let it sit awhile with fuel in the bowl. It wouldn't start. The float was stuck. I removed and cleaned the float, but nothing else.

The bike ran fine for awhile, but had a little backfire and popping on decel. Eventually the backfire worsened, it was hard to start and would not idle without the choke on.

I finally took the bowl of again and checked the jets. The leak and pilot jets were clogged with green funk. I cleaned all jets and bowl with carb cleaner and air; thoroughly.

After that the bike ran great.

I dont know how different your carb is from mine, but you might want to clean all jets and bowl again.

[Heywood]

Thanks for the reply. Yea, maybe I missed something when I went thru the carb. It sure sounds like it is a fuel delivery problem. I guess I'll have another bash at it....

[05BlackTaco]

hey i have a brand new 06 wr450 that i just picked up yesterday and when i dont have the chole on in neutral, within a few seconds it sputters and the engine shuts off...is there something wrong with my bike?

[Frostbite]

How's the compression feel? It's very common for condensation to form on the valves and cause them to stick open a bit.

Another common problem, especially since you have high idle, is a cracked or broken throttle plate. This would be like starting the bike with the throttle open and WR owners know what a pain that is. The plate may have been cracked and just happened to break when you tried to start this time.

The sticky float theory is the first one I'd look at but these are a few other options if that doesn't pan out.

[xrfunguy]

hey i have a brand new 06 wr450 that i just picked up yesterday and when i dont have the chole on in neutral, within a few seconds it sputters and the engine shuts off...is there something wrong with my bike?

there is nothing wrong with your bike if it is brand new it still needs some break in time all my bikes have done this untill break in is complete.

[Heywood]

Update - I found the problem I was having. Turned our to be a small piece of debris in the pilot jet. It took two tries before I got it.

Starts great and idles just like she always had. I wish you didn't have to disassemble the whole bike to get to the carb..... ?