please post here: YES woodruff key problems

utvols, feb. 03, #1321, MS, Less than 10 miles, no adj.

Two other bikes in Memphis with less than 20 miles with failure





5)Failed at approx. 50 miles


On a side note Yamaha told dealer to torque rotor nut to 61(I made them call twice) They also said they had no knowledge of the incert calling for 47 and requested my dealer fax it to them. :)





7.2 miles deep in the woods

dealer torqued to 61 lbs which was recommended by Yamaha. Yamaha insisted dealer not rejet carb. Yamaha said to richen with mixture screw only!


January 15th



Less than 20 miles

No adjustment

Alright, since I started this chaos by posting the first woodruff key problem, here is my info. My wr450 was purchased 1/10/03 in Paso Robles Calif. Serial NO. 1093. Had about 96 miles when keyway sheared. Bike was completely stock except for exhaust insert removed, and airbox baffle out. Stock jetting, throttle stop not cut. Happened when it backfired while starting with the button and hand on the throttle!! Hope this helps the cause. Leaving now to ride this weekend...can't wait!

law_boy, 1/22/03, Covina CA, 1018, around 120 miles.


Broken woodruff key at 32 miles, along with the left side case cover. Dealer fixed.

Now we are going back tomorrow for a shifter that doesn't want to come back up (now at 56 miles). Saw this on TT, that there is an adjuster that may iron out the problem. Sure hope so.

The Blue One,2-5-03,Checked torque at 47lbs,#1766

Broke at 130 miles.

EFM makers of the NO-STALL AUTO CLUTCH recently bought a wr 450 as a test mule. We notified the dealer of the problem, since several riders we have riding the auto clutch has them and have had the problem. Everyone has had the same failure. Were in Ohio, so rather that batch came here, but out of 5 that are here, all have failed.

Our new bike idling in the shop, it stalled, the when refired, held throttle open a little, pop and backfire, sheared key way. Even tho the dealer did the yamaha bulletin, which most dealers dont even know about.

We disassembled, found out the tapers are off slightly, lapped the flywheel in, took about 5 minutes with valve laping compound, 120 grit, works great. Tighten to spec, made it a day without a failure.

When we blued up the taper, they dont match, only by a few 10ths of a inch it is off. Lapping it in will ensure that you match up the taper, and you will know when it is matched, the shaft will turn a satin grey without any shiny spots.



A few 10ths of an inch! You mean tenths of a thou? How do you shear a key way? Maybe the key? Sorry, hate to be a wisenhiemer. It seems that this is caused by the back firing and the key doing its job? I am not saying lapping will not help, I just think the root of the problem is jetting. ----Mike

Talked to Yamaha today... They don't know for sure but they think what happened was a "pinch" in the airline on the tool used to assemble that particular piece. Also a dealer I talked with today that has fixed 4 of these said a bike right out of the crate had 14 foot pounds on the nut and it should be 50. After the replacement and re-torque there have been no further failures.

Mike Hobbs

replacement of what ? the woodruff key ?

so is it suppose to be 47 lbs. 50 lbs. or 61 lbs. ?

A re-torque will probably work, from what I've been told there have been no updates to the "key" itself. I'll have the official word from Yamaha in a day or so... I hate to SPAM this website but the latest info will be on ORC. I'll post it here as well if I have time. Don’t know the correct torque spec just yet but should know tomorrow.

Mike Hobbs

Mike thanks for the info.,love your write ups. Pinched hose heh? OK I'll bite.........I am struggling with all the conflicting torque specs (40,50,60?) in the manual on the very same part that is a failing.Is that a major coincidence or I am I just paranoid?

Now the second woodruff key went. The first one at 32 miles the second one at 72 miles (5 miles into the 1st lap of a Hare Scramble). Torqued to 47 the first time.

Serial 1286 :)

If the tapers don't match, you are not getting the correct amount of surface to surface contact to hold the flywheel in place on the taper.

First time post, been reading all about the problems with the WR450 woodruff key for a few months now. Saturday I picked up my new bike, and told the dealer to check that as I had heard about a lot of problems with the woodruff key. The mechanic called Yamaha, and of course they said they had no knowledge of a problem, so he refused to look at it. Sunday morning comes, I go for a ride, make it 12.6 miles and was seeing how easy it would bump start down a hill. Second time I did this, it started right up, but started sputtering and running like sh*t. So, limped it back to the truck, knowing what the problem was already, headed home. Went out yesterday morning to start it up, used E-Start, started fine, but ran rough, then stalled. ATTEMPTED to restart, loud backfire out the pipe, and THAT'S ALL SHE WROTE!

My number is 0389.

Has anybody been able to talk to Yamaha directly yet? I think we need to stand up to them and get it taken care of. We have a real short warranty on these bikes, and need to make sure they are fully aware of the number of problems.

Even if our warranty expires, if there are enough complaints, and they find it to be a factory defect, they should step up to the plate and take care of all of us!

If anybody has actually been able to get in touch with Yamaha, it would be helpful to the rest of us to know exactly how you did it, so that we can call too.




Several members have come up with some great ideas on getting to the bottom of the Woodruff Key issue. I would like to bring all the information together for documentation purposes. The 30 day warranty period is expiring for many new owners. I would strongly recommend that you contact your dealer concerning this issue and keep a record of the date you brought this up. By bringing together specific data, we can increase our standing if we run into further problems in terms of Yamaha taking care of this problem. In addition, we might be able to find a pattern related to production date, state of sale, miles and torque.


Please post the following (try to keep in order)

Name, date of purchase, serial number, state purchased (or county for outside of US), miles on bike at the time of key failure, any torque adjustment after purchase prior to failure..

No offense but I dont part. like lawers, but most states have consumer protection laws for just this type of thing I.E lemon laws. If someone has had 2 keys shear they shoulod tell Yamaha that they are contacting their States attorney General :)

I sheared keys twice. This time, Yamaha sent a new flywheel, instructed the shop to lap it onto the shaft, apply loctite and torque to 47 ft/lb. They did so and I had no problems racing it this past weekend. I richened my jetting before the race to stop backfiring. Serial number 1357.

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