Preliminary data on woodruff key failures

From my past experience, it takes about 30 in a group down the production line to make a prediction of what is to happen in the future. What you have right now is the best we at TT have. Thanks for the effort! I think the engine numbers would tell a better story. Frame numbers can be too far removed from the point of assembly of the shaft, fly wheel, and the torque of the nut. JMHO

Good analysis! FWIW, I haven't posted in either category yet as I've only run 1.7 miles on the clock due to weather (1.7 glorious miles). Mine is in the 670-something range and came in 2/10/03 in Baltimore, MD. It came with the add-in page and stickers in the manual. No clue on current flywheel nut torque but will check soon.


Excellent work! This is what Yamaha should be doing. Your data suggest a manufacturing defect and not a design problem. Thats actually good news. <ul type="square"> "Production (serial numbers)

From 1091 to 1766 = 100% of the failures in the study group. No failures were reported from 0-1090 or from 1777 or above."

It is interesting that the first batch shipped started with the 1000+ serial numbers, and all failures occured in that batch. Perhaps Yamaha knows they had a production problem, and fixed it before the second batch? This is great work. :)Please continue. Hopefully you will be able to give this data to Yamaha, and get feedback as to what they are doing, if anything, with it..... For those unfortunate to have a serial number in the 1091 to 1766 run, you can expect to have problems... :) Call your dealer.

This info makes me feel a little better about MY purchase for I have 0 miles on mine with prod.# 0602.I did however remove my ignition cover last night & checked torque.It was 47 spot on. :D

03 WR450FR-picked up 2/3/03. Works connection alum. frame guards. :)

Engine # is J314E-002376 to add to data base.

Good job all, way to show power in numbers. This site has helped me feel much more confident about this problem since Yamaha is setting on thier hands about a problem they know they have.

Loose rotor nut, no failure frame # 0413 engine #1168

The dedicated members of ThumperTalk will solve this problem for Yamaha. I think Yamaha should kick in some cash for consulting fees...LOL... :)

in the case of 1000+ being shipped first, then 0-1000 shipped later its far more likely that the first ones built were at the back of the warehouse and too hard to get to! they just the ones at the front first.



Does anybody think Yamaha would be willing to repair a woodruff key failure at no charge after the 30 day warranty has elapsed?Just hopeing because it will be April before mine sees the woods.

03 WR450F-grey wire,works connection alum. frame guards

here's my 2 cents, point one check flywheel torque first - before starting. point 2 the manual states on page 3-2 after breakin check rotor nut. Now since nothing has come through my yamaha dealer as far as problem with the woodruff key, which i trust very much, at this point in time i think that yamaha does not consider the current issues a problem. once again part of the problem sounds like RTFM. Final point - I did not have to do any type of mods on my 98 XR 400 but this WR 450 is a totally different animal. These new machines are high tech and need to be treated a bit differently. Do not misunderstand my final point, I plan on racing this bike a lot harder than my XR 400, thats why I bought it, I just mean that until we figure out the ins and outs of these new bikes some problems will crop up, and that it may not be a Yamaha problem its a uninformed user problem. RTFM RTFM

When you pay $6,000+ for a new bike you expect a machine with no design or production defects. I hope you don't expect less. My 02 Honda XR650L ran like a swiss clock without ever a problem, and I expect the same from my Yamaha. The XRL has electric start and I used it everyday. No-one ever had a problem with it or a "Woodruff key". This problem is Yamaha's and we should expect them to fix it or they will lose their market share back to Honda.

"may not be a Yamaha problem its a uninformed user problem"

I'm informed enough to know this is a Yamaha problem. They will fix it. Wish they'd hurry up.

hey alabama rider, hey adamwagar, did you check your flywheel torque yet, have you had a key prob ??.

And just another thought, wait til people start removing the neutral switch and the clutch lever switch, and start using the E button IN gear. That small key doesn't have a chance if the flywheel torque is low.

I'm in Northern Michigan, 8 below zero and three feet of snow. Wont be riding for at least a month. So, I have time to wait for the official TSB from Yamaha.

Like I've said before, I don't want to replace the crank because of a botched "Over the phone Fix".

Exactly, <ul type="square"> "That small key doesn't have a chance if the flywheel torque is low."

I believe the key design is too small. Yamaha will have to redesign to increase its size, which would be an expensive recall for Yamaha. Perhaps that is the reason we haven't heard from them. Yes I verified torgue at dealer and haven't had a failure, but am very careful when starting to NEVER touch the throttle.

I was talking to a friend today about E buttons in general and he said that KTM's manual states that there E button is to used after the engine is warm. Do you know it thats true.

Allinson -

Just a note to report that my #0996 WR450 just sheared the key after 54 miles (second ride).

If the dealer balks at doing the repairs, how do I hold the rotor while re-torqueing the nut after I get a new key ?? Its been 45 days since receipt of my bike, so I suspect the dealer will whine.

Rainman :)

ser#1243 canadian model 17 kilometers, checked key torque with snapon click type torque wrench,set at 45foot lbs to loosen. It did not click.retorque to 61 foot lbs as per manual update. noted that by looking backwards thought back of page orginal speck is 50 lbs.


When you pull the cover you will see the answer to your question, there is a built in hex on the rotor that uses a 15/16 wrench. It's shown in the manual pages 4-78 and 4-81 you should lap the rotor in just takes minutes.

Hey gxsrguy, my US manual came with a insert in the front of the manual. It said to torque flywheel to 47 lbs.

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