2000 YZ426 Shift Fork Question with Pics

Many thanks to TT and GrayRacer for helpful info and straight facts.

I've decided to update my crankshaft from the '00 keyed balance drive gear design to the splined joint design. The key slot in the crank had too much slop and would wear a new key within 1000 street miles. Now that I have the cases apart, I'm looking at all the gears and shift forks.

Shift fork #1 is clearly bent, so I will replace it and the related pinion gears. I'm not so sure about the other shift forks, so I would appreciate some advice based on these pictures. Shown is shift fork #3 with a slight trace of wear between the tangs (the crescent shape) and 4th wheel gear, specifically the dogs that engage 3rd wheel gear with a slight rounding of the corner. Should forks and gears that look like this be replaced?


Thanks for your help!

I wouldn't worry about the gear / shift fork shown in photo. Until the dogs round ends top side is not hit / worn / rounded completely off, they should work fine.

The fork doesn't worry me. That particular fork is subjected to the force of a gear bouncing out of engagement from one side, since it shifts only second, and the side shown is the opposite of that which bears the load of moving the gear into engagement.

The gear doesn't look bad in the picture, either. I see visible wear only at the lead edge of the gear. It gets to be a problem when it is worn farther down the lug, and this one doesn't appear to have much there. Be critical of the wear in the slots of the mating gear, as well. It's strictly a judgment call, since there's no practical way to see how much undercut remains on the lugs, but if it isn't any worse than it looks here, it should be OK. You have the advantage of having ridden the bike and knowing how it behaved before you tore it down. It doesn't appear there was any problem with that gear.

BTW, 4th gear wheel is moved by the #3 fork, and engages 2nd. 5th wheel engages 3rd. :thumbsup:

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