CBR 954 Undercut Transmission
 

I almost made it through this years drag racing season before my transmission finally let go. It got to the point where it would not shift into 2nd, 3rd or 4th gear at high rpms. Normal riding it would do ok. After removing the engine and splitting the cases I figured I would have to replace gears 1-4. While talking to my racing buddy he said my old gears could probably be undercut saving me the cost of buying new gears at $60-80 per gear. He called one of his sponsors who runs a machine shop and he said send it to him and he would check it out. Turns out even my old worn gears were still good enough to undercut. I got a great deal since my buddy knew the guy very well. Normal price for undercutting a transmission can range from $300-450. When you figure the price of new gears would be around $250-400 depending on how many need replaced why not just get your gears undercut instead of replacing them and hoping it does not wear out again. All the gears on both the input and output shafts were undercut but only for upshifting. If you do alot of track days then you may want both up and down undercutting.

Pics below are my stock gears before undercutting. Notice the wear on the dogs.

More pics.

More pics

so after this the problem with the gearbox they will finish? can you tell me how i can notice the difference between the stock gears and the undercut? thank you sorry my english =)

Yes there are no more shifting issues after having the transmission undercut. It shifts so smooth and quick now with no chance of it popping out of gear once the gears lock together. For anyone who is experiencing shifting problems having your worn gears undercut is much better than replacing them with new gears.

i have this problem i think,it happen 2/3 times (but not all togheter) that the gear popping out,but the mechanic told me that it was my problem that i didnt put good the gear..the last time that it happen i was running and when i put the 4th gear,and suddenly the bike pop out and went out of range with the 3th gear..so i must modify the stock gears for solve this problem?

Do you have the Factory Pro Evo shift kit? If not its one of the best upgrades for a 954 to improve shifting and decrease the chances of a missed shift. Also your shift forks may be worn or bent causing your problem. They can be changed without removing the engine.

no.. i have everything original on my bike..where i can find the factory Pro Evo shift kit? i know about the shift holder but no about this that you told to me

i read just now about the factory pro evo shift kit,it's completely different to the shift holder that i said before,and it'a s little mess for install.

marco did you ever find the solution to your 4th gear falling out? What you described is happening to me