Preliminary data on woodruff key failures

Engine 7755 frame 2996 16hrs running time at 400 miles. No problems and I have rode it hard. At this time my dealer cant get a key because they are on backorder. So I ride.

Mechanic stripped my new bike (Engine no: 9015) to do the flywheel and found the bikes are now comming lapped and loctited from the factory.

Interestingly enough all Yamaha dealers, worldwide, are receiving a bottle of Loctite 648 direct from the Yamaha factory in Japan for the mods. I saw their bottle, label is in Janapese showing its origin.

Had my first ride on Saterday, great enduro bike, love the chassis and suspension, power is not as crisp as the CRF but very good lugging bottom end. Perfect for the offroad application.

Only did 87km, but so far am very happy with my choice.

BTW, fitted a FMF Powercore 4, man this pipe is loud, wishing I had gone for an Akropovic or something.

so far so good !! 500 miles no problem,did the recall and rode 150 or so.still going good...

haven't done mine! just keep riding. have never received anything from Yamaha informing that I needed to take it in.

Does any one have the written material from Yamaha stating the procedures to fix /update the woodruff key problem. i.e. recommended torque, using locktite, lapping compound ect. I just pushed, pulled, towed my wr 450 through 31 miles of mountain single track. I don't recomend.

I lost mine during adesert rally, fixed it at night..retightened, locktite #7 etc.etc and failed nex day. Both days I used electric starter a lot seems that the woodrufkey doesnt stand the torque from electric motor. after that just use the electric in real urgent situations.

If it's failing, then the tapers aren't fitting correctly which would mean lapping them together is in order. Make sure you use Loctite 648 (cylindrical retaining compound for taper fit parts). The key does nothing more than line up the flywheel to the crankshaft. You might want to redo it if you didn't lap the parts together. :)

I found a new wr450f in the garage on fathers day morning, wow how the wife and kids could keep a that to themself for a few day is amazing. I know that the dealer did the yamaha req. "fix" on it, when I called he told me the fix was to add some locktite and tighten the nut to spec. My v.i.n. no. ends 2555 and my hope is by this time in the production run they made an unannounced factory fix. I know there is no underground word of this but I'm not sure yamaha would say anything anyway. Has anyone with a vin that high had a shear problem? Thanks to all posting they are a wealth of great info.

Sold a Husky 610 (also will bleed blue)

Silkyracer, if you still need the Yam TSB, I have it.

WILL BE PICKING UP MY NEW 2003 WR450 ON THURSDAY 6/26/03 NOW I AM NOT SO SURE I WILL BUY IT. IS YAMAHA FIXING THE BAD BIKES? SHOULD THE MOD ALREADY BE DONE WHEN I GET THE BIKE ? HOW DO I KNOW IF THE MOD IS DONE? DEALER DID NOT MENTION ANY PROBLEM'S WITH THE BIKE SH _T SH_T SH_T

DR1372

From all the info that I have gathered from this site and other means, it really does sound like there was a problem at the factory with a run of bikes. Maybe, and I think should have been caught at the QA/QC dept. They didn't have the flywheel nut tight as called out by the spec. Maybe it was a calibration issue with the equipment no one will say. But once the problem showed it ugly face Yamaha was somewhat forced to do something. Since they most likely don't know exacly what bikes have the issue they put forward a recall/fix for all the WR450s. I think the only real way you are going to know if your dealer first, did the fix and second did it correct is ask them face to face and then see if the dealership sent the paper work back to Yamaha. If they did the right thing I think you are good to go so get your truck down there and get that bike! You know you what it.............

Don't worry DR once you get out riding the WR all your problems will go away, it's just fantastic to ride!!!! Enjoy.

The TSB says to place a punch mark at the beginning of the serial number after the procedure is done. I know that some bikes that were bought before the TSB came out and then the TSB done later the mark wasn't always punched. However if it's there the TSB was completed.

My serial number is 1309. I did not have the failure but took my bike to the shop to have the service bulleting work performed in hopes to prevent a failure. They did the work as decribed in the bulletin and then the bike failed within 6 miles of riding. I took it back and they ordered a new rotor/magneto/flywheel saying that there was less than 50% of the tapered surface matching up. This tooks some time (1 month) but since the new rotor, the bike has completed two 2 hour hare scrambles and many hours of joy riding. I have used the electric start exclusively since the new rotor and no failure. I feel pretty confident at this time that it is fixed.

WELL THANKS FOR THE REPLYS TO MY POST I FEEL MUCH BETTER ABOUT BUYING THE WR NOW. WILL BE GETTING THE BIKE TODAY. ALSO I ALLOWED TO WATCH AS THE REQUIRED FIX WAS DONE :D MY DEALER GAVE ME A COPY OF THE TECH BULLETIN M2003-007A WHICH HAS SOME CARB SETTINGS INFO THAT GO ALONG WITH THE FIX.I HAVE A SCANNER BUT NOT SURE HOW TO POST THIS BULLETIN ON TT. IF ANYONE CAN TELL ME HOW TO DO IT I WILL GLADLY POST IT FOR ALL TO READ. WELL THANKS AGAIN FOR THE HELP CANT WAIT TO GET OUT THERE AND THUMP AGAIN THIS AFTERNOON CANT COME FAST ENOUGH :D:):D :D

just like to add my experience regarding this sorry tale of woe.

Ordered my bike before reading of woodruff key problems on this forum. Caught up on the info before taking receipt of machine on june 21st. Enquired about the problems with the dealer - he assured me the problem was only with an early batch of bikes and the only rectification he knew for was the checking of the torque on the flywheel nut.

Not completely convinced by his optimism I decided to follow the manual guidelines on break-in and check the nut as specified after initial running in. No need for a crystal ball to know what's coming next.

Stalled the bike after 11km on clock and it would not restart. Towed bike home investigated problem and found flywheel nut slack and key sheared. Not willing to wait (the shop I bought the bike from is 200 mile away) I manufactured a new key and following the Yam tsb refitted everything back together. I've only pottered about locally since the'fix' with no problems as yet, fingers crossed.

I've noted all theories and concur that

1 the key is for alignment not to transmit torque

2 If mis matched tapers between shaft and flywheel contributes to the load being thrown on key, shearing of key would result.

3 Yamaha don't appear certain as to the cause of the problem Re. belt and braces approach with Lap, loctite and Torque.

As this is the first new bike I've had that has let me down so soon and cost £5495 (approx $8000 -we get stiffed by the taxman good, here in the UK) I feel really sad that more information hasn't been forthcoming from the manufacturer and if it wasn't for this forum I would have thought that my problem was an isolated incident. Anyway the 23km that I have ridden fault free have been superb.

KGD :)

After several discussions with a senior Yamaha factory mechanic, it is obvious to me the root cause of the problem is a design flaw in the taper between the flywheel and the crank. By adding the e-start feature, a shorter, steeper taper was required. If you look at the YZ, the taper is much longer and less severe since there are no e-start gears on the crank. The shorter taper does not provide as secure a contact patch, hence the band aid fix of loctite to add strength. My guess is we will see this solution reengineered in the 04 model but without any mention from Yamaha. Just my .02 cents worth. :)

Gloft I would agree partially, and I may be wrong on this. With the taper being shorter it seems that they need to hold tigher tolerances on the taper and the flywheel mating surfaces. This would explain why some have failed and some have not, some are with in the tolarance limit and some are not. Now is getting this taper mating surface tolarances with in reason in a production setting??? Thats the question. If they tighten up the tolarances will they be able to use the same size shaft?? Just my $.02

Man, I've been off the WR side for a while and this is still going. I bought the 426 because of this issue. Was kind of bummed I didn't get the E-start at first but now with all the mods, the bike is a breeze to start. Jetting is everything!

<font color="black"> Brand new to TT but I'm already addicted. Just thought I would chime in. I picked up my '03 WR450F on 6-20-03 and was going to go on my first ride with the family this Thurs. 7-3-03. I went out in the garage today to fire the bike up, warm it up, maybe take a spin down the street and low & behold if while I was cranking the bike over it sounded like somebody clapped their hands and then NOTHING. The motor would spin but not fire at ALL ! Mind you, THE BIKE HAS NOT LEFT THE GARAGE SINCE I BOUGHT IT....0 MILES !!! My engine #J314E0005650....the last four numbers of my VIN#2448. Go figure. These numbers seem to be a far cry from the problem prone numbers and I am a little concerned I must admit. Paid almost $7000 OTD. When I got to the dealer he said that he has not heard of the problem occurring after "the fix" has been performed. It should be noted that there is a small peen mark in front of the VIN indicating the the correction has apparently been performed.?.? Anybody have any thoughts? Somebody please reassure me that I will love this bike as soon as I ride it...HA HA

I should clarify that the bike odo. actually says 1.1 miles...so it's not really 0 miles but I'm still surprised. :):D :D

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