hey guys new 01 cbr 929 owner here from aus.

In the progress of getting my bike to roadworthy condition right now so i can take it out on the roads legally

Its pretty stock apart from a short yoshi pipe, adj levers, flush mounts and gearing 15t f & 45t r.

Ive got a problem with my gearbox, the bike was owned by part of the crew in firestorm films here in aus, so i am lead to believe it copped abit of 3rd gear wheelie action.
3rd gear as soon as it is in gauged (even with clutch in) has a loud chattering noise. It doesnt seem to be slipping or jumping out of gear, or affecting the performance in any way though. I suspect 3rd may be missing some teeth? some mechanics i have asked said there is no way its a missing tooth because it would have blown a hole through the engine and that honda cbr's have very strong gearing, which leaves them puzzled on what it may be..

any advice on the gearbox would be greatly appreciated..

charlie

 

Inside your gearbox all the gears rotate and the shifter just pics which one gets linked to the shaft it's spinning on via your shift forks sliding a ring into them. I would speculate that you hear nothing in other gears because there is no load on 3rd gear. When you shift into 3rd, the gear is now taking all the forces involved in moving the bike forward, or engine braking. Most likely the bearing that 3rd gear rides on is trashed. The gear spins on it when not engauged, then sits stationary on it when it's linked to the shaft via the engaugement ring thingy. With a bad bearing the gear doesn't sit centered, it rocks around on the shaft as it spins. Sometime leave the bike in third with it chattering away and pull the cluch in. Coasting in 3rd will only have the engine idle and parasitic drag of the gearbox oil loading the gear. If it gets significantly quieter with the clutch in, I would plan on replacing that bearing before it has a chance to damage the shaft. Of course I am not a certified mechanic and take no responsibility for diagnosis or trouble caused by my suggestions...

 

thanks for the info, i didn't even think about bearings.

i think i will have to pull the engine and change it, because it sounds like you are on the right track.

 

Remember also that your gear oil and motor oil is all the same in bikes, so do an oil change and chop the filter in half with a hack saw. Besides the metal from cutting it look for shavings in the filter medium to indicate something shaving away inside.