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cadvette

03 WR Won't run

11 posts in this topic

Went out rideing this weekend and got a few miles into the woods when my bike started backfireing a missing. No big deal, thought it may have just fouled the plug. So we stopped and changed the plug. It looked good but changed in a new one since we had bike apart. Put every thing back together and it fired up and ran fine. then about after an other hour on the trails it started missing and backfiring again put would clean its self out. So we kept going. Now when I would come into a corner I would clutch and let off gass and it would stall like I had hit the kill switch. Let clutch out restart keep going. After I hit a big long stretch of Whoops the thin g just died and never started again.

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Went out rideing this weekend and got a few miles into the woods when my bike started backfireing a missing. No big deal, thought it may have just fouled the plug. So we stopped and changed the plug. It looked good but changed in a new one since we had bike apart. Put every thing back together and it fired up and ran fine. then about after an other hour on the trails it started missing and backfiring again put would clean its self out. So we kept going. Now when I would come into a corner I would clutch and let off gass and it would stall like I had hit the kill switch. Let clutch out restart keep going. After I hit a big long stretch of Whoops the thin g just died and never started again.

Have you checked to see if the woodruff key on the flywheel has been gone thru? Many of the '03's had issues with the machining on the flywheel and would shear the woodruff key! Do a search to find out all the info. unique to this year model.

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The woodruf key issue has been taken care of. We got the bike backe to the garage and checked the keyway and it was ok. We took out the plug and it was good checked for spark it was good. So I put in some fresh gas and it fired rite up and seemed to run fine. off to the trails we go. on the way to the trail bike ran strong, but once on the trail about 1 mile in I slawed for a corner and it all started again. Backfired, missed then died.

This is my bike setup. I am running 48pilot, 162 main,stock needlein stock position with the fuel screw 1 1/4 to 1 1/2 out. Air box snorkel out. Stock exhaust with GYTR insert. This setup has been great for me with no problems till now.

I didn't get home with the bike till late so I have not cleaned it or taken it apart to see what is up yet. I planned on cleaning the carb, checking valve clearence and doing a lot of checking with multimeter on a lot of the electrical components

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Check your ignition coil. I know you said you have good spark but my 2003 WR450 did alot of the same things yours is doing when the coil went bad.

Especially starting and running just fine when the engine was cold, but as soon as you warmed it up for 3-5 minutes then it would start acting funny. Mine would constantly stall when doing corners, and low rpms.

I troubleshooted my jetting, the ac pump, valves, and an auto-clutch for a year and half before I discovered that it was the coil. If you have a buddy you can swap coils with, any YZ,WR 250 or 450 coil will work as a temporary test to see if that's the issue.

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Water in the carburator ?

Gas floats on top of water.

Will run straight (if not too much water) but in turns and whoops the water will start going into the cylender and the motor stalls or dies. Usually starting again is no problem on a level surface.

There is this 3mm allen screw under the carb that you can release to drain the bowl.

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Its not water in the gas. We drained the gas and put new in at the pump and we also drained the carb before we put fresh gas in. with thew fresh gas it did the same thing.

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sounds simple and stupid, but make sure there isnt a short at the kill switch.

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That was one of the first things we did. Took off the check valve and just reconnected the hose. seemed to make a difference until I really got on it on the trails. Then all of the same symptoms started back up and it died. Will be out in the garage this weekend doing allot of testing with my meter. I will also be checking the wiring harness out real good looking for frayed, burnt or broken wires.

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Was just reading an article in Dirt Rider about how the sent a YZ250F to Pro Circuit for engine mods and when the put it on the dyno it kind of did the same thing as mine. they changed the coil, cdi, stator withe no luck. Come to find out it was a faulty kill switch. I will be checking that for sure. Also I didn't mention that I have a Baja Designs kit on it. Wouldn't surprise me if the problem could be with that. Won't be the first time.

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