'03 WR450F Woodruff Key Blues

I just emailed this to customerservice@yamaha-motor.com and president@yamaha-motor.com

Dear Sir:

I just thought your company should be aware of the concerns of the newest WR 450F owners. This is a link to Thumper talk.com. There have been alot of failures of the woodruff keys on the flywheels and many prospective customers are doubting the reliability of your product.

Thank You for your time

I tried to email Yamaha but I think because of my hotmail account it would not send. Could someone please forward this message to Yamaha.

I own a 2003 Yamaha WR450 VIN # JYACJ04323A000641.

Purchasing Dealer, Extreme Powersports (989)732-4331

Has it been recalled for possible woodruff key failure?

Is there A sevice bulliten pertaining to woodruff key failure?

Thank you for your consideration,

Adam Wagar

Gaylord, Michigan

From Yamaha - to Adamwager

Dear Sir,

You should have bought a Honda :):D

i took care of this adam....i'll keep you posted :)

crap....it came back "undeliverable" .

Thank You. :):D :D

I mean, thanks for the attempt. Same message as I got. I guess we need a different address.

I still have my XR400 for backup. :)

mannnnnnnn... i dont even have a back up.

hmmmm...can i borrow the XR50 ????? :)

About a month ago I wrote a post on what I found on my own bike. I checked the tapers between the flywheel and shaft with spotting dye and thought that they should fit better than what they do.It only took about 20 minutes to lap them into each other ,probably less time than I can change a spark plug in this bike.

Yes it might be a Yamaha problem,no a 6 thousand dollar dirt bike should not have this problem .But it does.It is a easy fix and I would rather have my bike and fix it myself and go riding than wait for Yamaha or dealer to decide there is a problem.Jet it so it doesn't backfire(thanks for the info Utvols,keep it comming)Lap,loctite and torque the fly wheel

then go ride the heck out of it!

Since I fixed mine three weeks ago no problems .Rechecked

fly wheel nut torque yesterday it was right on.


You got to think about what this guy said. If the torque is what holds it together, than why us less torque? Are you stripping the threads or are you shearing the threads? You would know that when you did it. Is the Key supposed to hold the force?

I agree wholeheartedly! IMHO LMAORITF! :)


I was just searching for that post. You are exactly right about fixing it. Just do it yourself and stop the worry.

What was the heading of the post?


I think you are right on. The match up of the taper of the crank and fly wheel must be off a little. When I poped the flywheel off my WR400 there was a very loud pop, that think was on there. The tapers have an enormous amount of hold. The 47 lb vs 61 lbs of tork shouldn't matter if the tapers match up. For the bike to backfire and shear the key just doesn't make sence to me. I bet the pitch of the tapers are off by a bit.

Sputter, I like the way you think and say it! :)

i bet we'll see something about woodruff keys shearing, in the magazines.....in about 6 months. lol.

thumper talk rules. :)

Thus far my WR runs like a champ! It always starts on the second, 3-second burst I give it with the E-start. :cool:I have only gotten slight backfire, when hot, using hot-start. I have found that if hot, and the first 3 second burst with hot-start on doesn't start it, then I release the hot-start and it starts right up on second burst. <ul type="square"> I found on my XRL with E-start that a 3 to 4 second burst is all you should give it.

It will start then or never. You need to change something and give it another burst..... I am starting in above 60 degree temps. This is probably a factor in such easy starts... This is such a great handling bike, it is a shame its introduction is tarnished with this problem. I really pushed it hard today and several times thought I was history, only to recover unscathed.... :)I do believe that a solution is forth-coming. RIDE-ON.

We need to bring all of the post on the woodruff key together for documenation purposes. I am going to make two new post, one for those who have not had any problems and one for those that have. The information will be specific and limitted only to the woodruff key. I am going to ask the moderator to keep these two posts together and to stay active on the first page.

I'm wondering if Yamaha knew they had a slight fit problem and thought that by going with a higher torque (originally 61 lbs.) on the nut, they could slightly reform the shaft or flywheel?

Has anyone taken these apart and measured the taper angle on the shaft and the inside of the flywheel? If they are not the same angle, you are not getting the full contact strength of the taper fit.

I know someone mentioned using Dykem layout fluid but I haven't seen anyone report whether or not this was used.

Hi, my tech english is not as good to get that WOODROOF KEY, what is it??


It is the small part that fits into a slot to line up the flywheel.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now