WR450 Starter Update '03 to '04 Part Numbers

I did the same thing Tim before even starting the bike. No problems yet. My worry is the starter gears going out now. I should just buck up and buy the 04 parts.

All this starter failure talk has got me paranoid, so I ordered my parts today. The dealer I buy from discounted all the parts to cost, so the total was less than 150.00. I will let you know when everything is in!! :)


WR250, You are mistaken. You did not have a woodruff key failure. Yamaha customer service told me the problem is solved. They had not had "any" reports of failed keys since they published the TECH BULLETIN......

Yamaha is singing " I got time on my side ". They will let this issue solve itself. In other words we are on our own to upgrade the parts if and when we have failures. :)

Since they haven't had any more failures since the Tech bulletin I guess they changed the '04 just for the fun of it. :)

im gonna have to bite the bullet and get these parts in myself. i want to sell my bike and cant sell with this problem. it will be cheaper to buy parts, than lose money on depreciation. doesnt look like yamaha are in any hurry to sort things out. still havnt heard if anyones been successfull with upgrade yet. please let us know. thankyou

I'm going to sell mine or trade it in. I can't trust it.

I wrote a letter to Yamaha and someone actually called me.He said that since mine had failed and had been repaired by the dealer per the t.s.b.,then I should have no more problems.I did not argue. "F*@# it! Screw them!

O.K.,fine.He's not the one that had to push that heavy [@#$%&!] out of the woods when it failed at less than 150 miles. I don't want to do it again.

You guys who have had to push a WR450 for any distance. know what I'm saying.

I am a 48 year old vet,been riding since '69 or '70 and NEVER have I had LESS confidence in a motorcycle!

I'm going back to Honda. They are just better.

(just my very experienced opinion)

Interesting item in the Feb. '04 Dirt Bike Magazine's article on the '04 WR450: The crankshaft/rotor diameter were increased by 2mm. The article mentioned the flywheel key shearing problem on the '03 model.

Hay! my 2003 wr450 starter broke,taking out the coil, stator, sidecase, bearings,gears,bolts, etc.$ 500.00 +

I think that maybe there might be other cases out there.

Please help . Thankyou


I spoke to Jim Owen at Yamaha Customer Service in California. He said they haven't heard of one REPEAT failure of a WR450 after it was serviced to the TECH BULLETIN spec. :) Then he said they only consider received letters, when counting failures. He said "before the Tech Bulletin we were getting bombarded with letters and phone calls. We are not getting any now. We consider the problem solved". He said the address to send letters to is:

<ul type="square"> Yamaha Motor Corporation USA

Customer Relations Department

P.O. Box 6555

Cypress, California 90630

They have no plans and will not help at all with upgrading the 03 models to 04 models unless it becomes a major visibility issue. In other word, you are NOT making enough noise with YAMAHA. If you have not written a letter, then quit complaining. There is already one written which you can copy.

Date, 2004

Yamaha Motor Corporation USA

Customer Relations Department

P.O. Box 6555

Cypress, California 90630

Dear Yamaha,

On (date) I purchased in good faith a 2003, WR450F from your dealer xxxx, located in yyyyyy. Since that purchase dozens of Yamaha 2003, WR450F’s have reported failures due to a design flaw in the woodruff key starter system. The failure rate of these bikes has been calculated at over thirty percent (30%) within nine months from date of purchase.

Yamaha Engineering has recognized the engineering design flaw as evidenced by their complete redesign of the woodruff key starter system for the 2004 model. A retrofit to the 2004 design from the 2003 model is estimated to cost including labor around $700 list price.

Yamaha issued a “Technical Bulletin” number M2003-007, informing dealers to put the loctite 648 glue on the failed 2003 models crankshaft. Many who have had this fix have had repeat failures. This is unacceptable.

Please inform me when I should bring my WR450F to my dealer for them to do the woodruff key starter system upgrade to the 2004 model at Yamaha’s expense. I expect this will be handled in an expedited manner.

Thank you for your help. I will be awaiting your response.


My name

My address

cc: My dealer – his address

I just recently bought my 04 WR450. 2 days later my stator is broken. Is anyone else having this problem???? The stator is also backordered! The dealership first said it was the regulator but soon found they were wrong!! any advise???????

What do you mean by ",the stator is broken?" Are you not getting elec. charge or is the stator physically broken as in craked or something?

Got the 04 upgrade parts in today! Well they arrived way earlier then I thought. The torque limiting starter gear is really quite complicated and now I see why it costs over $200.00 list. Well the question now is how long can my bike go without needing the parts? :)

Well the question now is how long can my bike go without needing the parts?

Indy you gonna do the up grade now or only after a failure, if that comes??

I am debating on when to get to it. I have been busy but the winter time is the best time to do it. I might get motivated and do it next weekend. I will let everyone know.

Some guys aren't shearing woodruff keys, they're cracking cases. You're going to kick yourself if your case cracks and you had the parts the whole time...

Do you notice that the manual for the 03 wr450 has a starter clutch on the flywheel to prevent back drive to the starter mechanism. I wonder if that is the culprit for some of the bikes out there. If the clutch wont free spin backward. Anyway there are very few broken cases due to this issue and my bike has ridiculous miles on it in one year without a problem. But I will probably get to it before spring.


I'm sure you easily have double the mileage on your WR as I have on mine (probably more) and at 2500+ miles I'm confident I won't be having a failure. Like you, I haven't had the TSB done. I have been contemplating doing the 03-04 upgrade, however, simply because I miss having peace of mind everytime I go out.

Many of us are anxious to see how this upgrade goes so get busy! :)

Now I havn't looked really close at the stuff but got the feeling from some post that there was some sort of thing on the 03 starter gears that allowed some movement backwards but that it didn't function 100% of the time on some bikes. I'm I understanding it wrong?

I have not had the flywheel off. The manual shows a one way clutch attached to the starter gear on the main crank. If this is the case and it works we should not have starter motor pinion failure issues. For you guys that have sheared the woodruff key have you checked to see if the one way clutch was working properly? :D Notice that the 04 has a 2mm larger diameter crank to hold the flywheel. I am beginning to think that the 04 upgrade parts are not going to do much to prevent woodruff key failures. I think Yamaha did both to the 04 but the larger crank may be all it needs and the pinion torque limiter may be a panic reaction by the Yamaha engineers for starter clutch failure issues. I dont feel very confident that this is the solution for the members that have had the failures. Need more analysis. :)

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