YZ426f 4th gear gone

4th gear is gone in my 2001 Yz426f. It happend when I was on a wheelie shifting from 3rd to 4th with no clutch. Its just plain ole not there anymore. Any ideas on what parts I may need? How complicated is it to fix? Any advice would be greatly appreciated.

Thanks in advance.

Depends on what's broken. Most likely the 3rd and 4th pinions (on the main shaft) and the forward shift fork at a minimum. Of course, you'll want to carefully check the bearings while you're in there. The complication is that the entire engine excluding the head itself has to be disassembled.

I am presently doing the 4th gear on my 400 which I suspect will be very similar to the 426.

I noticed a whine when riding in 4th which gradually got worse.

When I stripped the transmission both 4th gears had lost their hardening and were quite badly worn, fortunately no other damage and the shift fork was fine (before the repair there was no history of jumping gears).

As Gray says, the complete engine has to come apart so it is well worthwhile to consider replacing bearings, seals, cam chain etc.

i started with my gear box jumping out of 5th oh how i so wisshed id left it jumoing £1400 later 1200 in parts

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