I need WR426 advise BAD!!!!!!!!!!!!


May 10, 2001
I have a brand new 2001 WR426, here is the deal.
This bike has 100miles on the 4th ride
On the 3rd ride: terrible clanking noise from left side of case. After removing the case, the flywheel & Stator, Stator magnets flew off destroying the inside of the flywheel as well as the stator.
Yamaha warranteed: new flywheel, new stator
These were installed correctly.
On 4th ride: Bike ran fine for first ride 20-30min. After cooling down,restarted ran fine for 10min. At idle again the terrible clanking noise. Again the stator & flywheel destroyed.At first I assumed the crank must be misaligned or installed incorrectly. But, there is no vibration, when the bike is running ok. Then we checked for play in the crank arm that attaches to the stator & flywheel. No play. The kick starter has no binds or kinks in the stroke.
I am at a total loss. I sold a XR400 that was plaqued with demons. I do not want to go through this again. I also own a YZF426 that is awesome! No problems:cool: :scream: :scream: :think Any help will be drastically appreciated by myself & MXTuner. Thanks


Sponsoring Member
Dec 30, 2000
Sandbar, NY

Wow, thats the first real engine nightmare story I've heard regarding the WR's.
My only take is this: Did the dealer cover it the second time around too? I hope for your sake they did. Sounds kind of weird that it occurred twice......


Damn Yankees
May 14, 2000
Geeze,...the only thing I can think of is the crank, or the flywheel, is out of balance, causing a nasty oscilation at a specific RPM. I would insist that Yamaha replace the engine and/or crank and flywheel. This type of imbalance would ultimatly destroy the entire engine. You may not be able to feel it while its running.


Aug 22, 2000
With a counter-balanced engine, you won't feel an out of balance crankshaft.

Get the shop to replace the crank. Even if you have to eat some of the cost. Don't have them check the balance. There's probably only 2 or 3 shops in the U.S. that have the ability to do that correctly.

Also, while they're in there, have them check the main bearing surfaces in the case very carefully. If the crank has been running twisted/bent or out of balance, the bearings can wobble and oval out the bearing journal areas.

Oh, and another thing -- make sure they check the balancer gear and its bearings for wear/alignment also.

Most shops don't think about this peripheral stuff.
Last edited:


May 10, 2001
DualSportR & Shaw520 Thanks for the assist

Thanks for the assist. I will be taking this beast back to the dealer tomarrow. My conversations have been very positive with the service mgr/owner. I guess it helps that I have purchase 6 Yamaha's in 3 years, 4 from this dealer alone. The dealer has told me "no problem" you are one of our best customers, even though I am just past the warranty period.....DualSportr thanks for the other things to check/look for, I have compiled a list from your recommendations,to ask them to check/replace. I will post either a very positive or negative report based on my experience.:cool:
Top Bottom