03 450 WR Key

Had a chance to ride an 03 WR450 this week.Borrowed the bike from a gentleman who works for a major motorcycle company as a rep, Not Yamaha. Had split the key twice and repaired by one of the local bike shops near North bend in WA. Dragged it out to Bellfair, east of Seattle. Nice ride until it backfired in the middle of a corner and spit me off over the bars. What is the cause as you on this site see it? anyone got a handle on a fix? Been thinking about a new WR450 and after the 1 mile push, Up hill, I am having second thoughts. Funny, My Cannondale never quit running, overheated, leaked, broke and it handled better than the WR. Maybe a WR with Ohlins after yamaha gets them to run more than 15 miles at a time. :thumbsup:

wow, we've only been through this a few times. use the search feature and you'll find alot about this topic. the short version. '03's are jetted very lean. if the engine back fires (a result of being lean) it will force the motor backwards against the starter clutch system. the engine will try to stop spinning and the inertia of the flywheel will shear the key. when this is repaired again, make sure the dealer is following the factory service bulliten. fatten up the jetting (again "search"). if you want to do it right you'll need to update the starter system to '04 parts also. $200.00 to $300.00 bucks.

Thanks for the info. Been sometime since I have been on this site.From what I gathered the dealers seem to think there is no problem. I sugested that we lap the flywheel and locktite it to the shaft, But sounds like the 04 parts fix the issue. Bike has a jet kit in it. Starts right up, Runs great. I loved the power delivery, Handling needed work and the tires left something to be disired, But not a bad scoot.

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