2000 yz426 woodruff key / 'cb gear' worries

Hello all:

I've spent a good amount of time searching for details on the woodruff key // cb gear clanking that is inherent in the 2000 yz426's. Right now, for some reason I can't search the forums, but that's beside the point.

I'm going to tear into the motor a little bit before the riding season starts, and i want to order some parts before i open her up.

My question is: The woodruff key that gets worn, and then has problems: is this the actual "woodruff key" on the crank (which would be accessed from the stator side of the engine) or is it the "straight key" that is located on the drive gear, which would be accessed from the clutch side of the engine? I have seen posts talking about taking the crank side cover off (clutch side) and checking for counter balancer drive gear slop, but then there is mention of the woodruff key...which if I'm reading the manual correctly, would be accessed from the other side of the engine.

I'm going to link to the image of what I'm talking about. If anyone who has experience with this could identify which parts are actually the problem parts, I would greatly appreciate it. I plan on making a step-by-step walk through, with pictures in case anyone else that has this bike needs to go through this as well.

Everyone has been very helpful in the past, so I'm hoping I can expect the same great support!


It's the square key on the drive side, item #9 in your drawing. It's a misnomer to cal it a Woodruff key.

Grayracer: As always you rock. I can always rely on you to clear things up!

Thanks again!

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