'03 WR 450 dead 10 min after I bought it.

I just bought this bike,it is as new with very little use and bone stock.10 min into my first ride I stalled it in a turn,I don't know how hard they are to start hot,but after 3-4 min it started but ran like crap and stalled out 30 seconds later.I let it cool(cause it wouldn't start) and it started and ran perfect for about 2 min,then started breaking up real bad and quit for good.

This is my first 4 stroke dirt bike and I'm not off to a very good start. :banghead:

Any ideas guy's before I dig into this thing???

I just read about the woodruff key problem,but don't know if it has been updated or not.What are the odds this wood happen to me in 10 min. when he had no problems in 2 years. Thanks for any advice.

Dude I hope that I save you here...I had a similar problem with my 450 this week.... Mine was brand new and the first time I got back in the woods I got similar symptoms after a few floggins. I rolled to the truck, checked the Grey wire, took off the tank and checked for flow, took out the plug...then grabbed the carb and the mutherfugger was broke loose from the head. :banghead: Just had to reposition the throat back on the head and wwwrrrrraaaaaaant.....wwwrrrrraaaaaaaaaant.......

Check the vent tube out of the fuel tank cap has not got a twist in it. Sounds like its starving for fuel, or crook high speed coil, breaks down when it gets warm. :banghead:

Update. I tried it again this morning and it started instantly and ran perfect. Whew, that rules out the timing/key problem. My son said it did the same thing with him earlier. Sounds like after it gets hot it just quits. It runs perfect leading up to that, so it must be something related to temp. I will do the plug/gas/carb thing anyway since I don't know the history of the bike. :banghead: In the short time I have ridden it, I must say that I'm other wise impressed with the bike. :banghead:


Reading what you said here, and re-reading your first post have got me thinking that you might have a jetting issue. If the bike runs great until it gets hot, this probably means that your jetting is running too rich. You need less fuel when the bike is hot vs. when it is cold.

What “exactly” is your bike doing? We need specific details of the symptoms.

Does it run like crap during idle….low rpms…..or high rpms?? All 3? A combination of the 3?

Does it pop and backfire on deceleration? Does it stumble and go anywhere in the rpms?

You said you stalled it coming out of a turn…How fast were you going through the turn? Was your throttle closed? Did it bog and stall when you first turn the throttle? Or did it stall as you were coming into the turn?

Like I said, specifics are needed. Also, knowing what your Jetting is needed too!

Try to fill out as much as the information below as you can.

Model (400 - 426 - 450): 2003 WR 450

Timing (WR-YZ?):

Main jet: ??

Pilot Jet: ??

Fuel screw (turns out): ??

Needle model/Clip position: ??

Airbox lid (on or off):

Pipe: ??

Altitude where you ride: Florida

Temperature where you ride: ??

It fired up instantly the next day and ran perfect.I rode it easy for 20 min purpously to get it to act up,but it did nothing wrong.I even turned it off while hot to see how if it would start,and again,it started instantly.Next I'm going to run it hard and see what happens,cause this is exactly what happend the other day.It cruised around fine,then acted up when I started to get on it hard.Results to follow. :banghead:


Large swings in temperature and humidity will affect the performance of your jetting.

I know this sounds basic, but are you sure the hot start was not engaged and that you turned the choke off after it warmed up? A few times I have forgotten to push in the hot start button and it runs good but then craps out.

just a idea if it sat there could be watter in the gas or carb

just a idea if it sat there could be watter in the gas or carb

This is the right track. If the bike sat the gas would collect water from the temp changes over time. It will probably start and run fine as long as you don't get on it hard. Popping and sputtering right before it dies indicates LEAN mixture. What is probably happening is you have water in the fuel bowl which sits there doing nothing until you ride hard and stir it up or get into the main jet enough to suck it up into the jet then you clog your main jet. Most likely since the pilot jet is right next to the main that blob of water is clogging the pilot also as the engine dies and you close the throttle. Drain ALL of the gas from the tank and lines, REMOVE the fuel bowl from the carb and remove the main and pilot jets. Blow out the jets with air and clean and dry the bowl then put it back together and try it. This shouldn't take more than an hour to do. If this doesn't fix it then look at the ignition.


Thanks again for all the replies.However,since that first day of it not wanting to run correctly,or run at all for that matter,It hasen't missed a lick.It's a mystery right now.I'll keep you posted if it does it again. :banghead:

Remove the float bowl drain plug and look for dirt. There may be moisture or corrosion lingering at the bottom of the drain plug.


Could it be jetting? Could be running lean if it's set to stock, right?

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