ttr 125 transmission problem

need some advice on a 2003 ttr125 yamaha

the transmission had a few gears that got some teeth broken off after the bike was laid over.

the main drive gear was missing five teeth and the 1st gear missing two. 

we got all of the gears on the new main drive axle and put it back together in the case. we started putting the shift forks and shift cam in and realized that once in, you could not shift more than three gears. 1 down and four up transmission. so we tried some trial and error since the book didn't show where the forks needed to be installed in the shift cam. turned out that the most we could get it to go is 3 and then up half way to four when it completely locked up.

what is going on? is there a specific position to install these shift forks in the cam? everything is in good condition so i know its not a bad part.

Do you have the genuine Yamaha service manual?


I don't have any suggestions specific to your bike, just some observations from rebuilding my Honda.  Are the case halves together when the transmission locks up?  On my Honda, I was going through the gears with the right case off and it would lock up in 2nd or 3rd.  But, when you tried it with both cases together, it would not lock up.  The issue was that without the right case half, the shafts were not held in proper alignment.  Just a thought.

good thoughts there.  Be sure you have the correct shift forks in the right order.  second is to measure the forks and check that they are not bent

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