Late 03 WR450's

I read a post some time back where someone wrote that their dealer had said Yamaha corrected the flywheel problem at the factory after frame #2694. My dealer told me the same thing however, he did'nt know how it was corrected. Anyone know more about this? Did they just loc-tite the flywheel or re-design? Did they change the starter clutch/torque limiter?

My frame number is 2849, anyone with a # past 2694 had any problems?



I posted the thread. The bulletin only says that the bikes outside the range were modified at the factory.

Hi my key went with about 1100 miles on it #4226. I wasn't to impressed .When I bought the bike I was told the problem had been fixed on mine before delivery ,I don't know how,but I dont trust them anymore or the bike. Dan

I have #1511 and I called my dealer today and was told that mine was not on recall list. I have 600 miles on it with no problems with key (that I know of) Course the bike never has ran correct. Is my dealer just brushing me off? :)

It's all in the jetting. You have to dial it in. What are your specs now? have you tried jetting changes?

The true fix is to have the 04 idler gear assembly installed. It is easy to tell if it was done by looking at the shape of the idler gear cover. The 03 cover is flat and the 04 is "bumped out". There are photos of the two covers elsewhere in this forum. While correct jetting will stop the backfiring that creates the conditions that cause the flywheel key to shear along with other problems (ie broken cases) the extra insurance of having the new idler gear is really the correct fix.

I am fortunate enough to be dealing with an excellent dealer and Yamaha Canada which understood from the start that there was a design flaw and did the right thing by me (all repairs have been warranteed). :)

willy fitz

03 WR450F

What is the symptom when the key shears off does the engine lock?

When my key sheared I had stalled the bike attempting to junp over a log. The motor did not lock but just quit since the rotor was just spinning on the crank therefore no electrics to make a spark.

It is extremely unlikely for the sheared key to get into the motor and cause major damage because when the key is sheared it tends to peen the two broken halves into their respective keyways and the rotor does not have the room to move far enough away to allow the broken key to escape.

That being said there are other parts that can fail that could lead to serious damage. There are a number of other posts that cover this.

willy fitz

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