1988 CR125R
I bought an abused bike in feb, and rode it once and noticed that third gear didn't engage, it was as if the bike were in neutral
I tore the motor apart and noticed that the shift fork had a grove worn into it. what was happening when third gear is selected, is the fork isn't pushing the dog teeth on the gear far enough into the other idle gear so the bike is essentially in neutral (no power being transmitted to the output/counter shaft).. I filed minimal material off of the shift fork, so that the gear sat flush again in the fork in hopes that it would engage itself again. While the cases were still split, i tested the shifting and activation of third gear and it worked flawlessly.. However the first time I rode the bike, I shifted into third and my "missing gear" problem was back. The wierd part is that the gear will take load while engine braking, however I can't apply power.. When i roll on the throttle I'm guessing there is enough lateral thrust to disengage the dog teeth from the face of the other gear.. I'm assuming this was an on-going problem with the bike before I bought it, because the dog teeth have been slightly rounded on the leading edge. The gear face that they insert to shows no wear.
I have been looking for a while to find used parts (since I first diagnosed the problem in feb), and finally have come across a guy parting out his bike..
My question is, do you think a new/used shift fork will fix my problem? The guy is willing to sell me all three shift forks, the shift fork rails and the gear select drum.
My secondary question is what would cause the gear to not sit flush on shift fork?
Sorry I have no pictures because I never thought to take any while I had the cases split, and the motor currently assembled in the bike. The motor, tranny and clutch all work MINT otherwise. I just wish I had third gear, the distance between second and fourth is pretty big while trail riding, and it's annoying having to shift 2-4 every time.
edit. I should have put this in the Mod/Performance/Repair section, can a Moderator please move this for me?
I bought an abused bike in feb, and rode it once and noticed that third gear didn't engage, it was as if the bike were in neutral
I tore the motor apart and noticed that the shift fork had a grove worn into it. what was happening when third gear is selected, is the fork isn't pushing the dog teeth on the gear far enough into the other idle gear so the bike is essentially in neutral (no power being transmitted to the output/counter shaft).. I filed minimal material off of the shift fork, so that the gear sat flush again in the fork in hopes that it would engage itself again. While the cases were still split, i tested the shifting and activation of third gear and it worked flawlessly.. However the first time I rode the bike, I shifted into third and my "missing gear" problem was back. The wierd part is that the gear will take load while engine braking, however I can't apply power.. When i roll on the throttle I'm guessing there is enough lateral thrust to disengage the dog teeth from the face of the other gear.. I'm assuming this was an on-going problem with the bike before I bought it, because the dog teeth have been slightly rounded on the leading edge. The gear face that they insert to shows no wear.
I have been looking for a while to find used parts (since I first diagnosed the problem in feb), and finally have come across a guy parting out his bike..
My question is, do you think a new/used shift fork will fix my problem? The guy is willing to sell me all three shift forks, the shift fork rails and the gear select drum.
My secondary question is what would cause the gear to not sit flush on shift fork?
Sorry I have no pictures because I never thought to take any while I had the cases split, and the motor currently assembled in the bike. The motor, tranny and clutch all work MINT otherwise. I just wish I had third gear, the distance between second and fourth is pretty big while trail riding, and it's annoying having to shift 2-4 every time.
edit. I should have put this in the Mod/Performance/Repair section, can a Moderator please move this for me?
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