08 YZ450F 4th gear slipping

When i shift it into 4th gear its like the gear isnt even there. 3rd and 5th gear are fine its only 4th gear. I am tearing down the motor right now but wanted to order the parts today so they will be in on time for my race. Is it most likely the 4th gear pinion or the 4th gear wheel. My guess it the dogs on the 4th gear wheel a rubbed off. Do you think the shift fork is bent as well? If so which of the 3 shift forks would be bent? Thanks

The 4th wheel gear engages second gear, not 4th. If 4th were to fail due to damaged dogs, the problem would be with the 3rd and 4th pinion gears, and the #2 shift fork.

It would be advisable to wait until you have the engine open to determine your needs, as the 4th wheel may also be damaged, as might any number of other components.

Thanks for the help. I tore it all down last night and it was the right and center fork. The left fork had no wear marks.

Critically examine the third and 4th gears on the main shaft. If the locking lugs show ANY wear and/or rounding, replace them. If you don't, you'll be taking it apart again, and ruin your new fork in the bargain.

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