FZR 250 gear trouble

[huboola]

I'm looking at buying a cheap FZR 250 and was hoping to get some advice. At the moment the bike runs fine with the exception that it sometimes has trouble changing gears. If you fiddle with the shift lever and the shaft it hinges on to, the gears work again, but it soon stops again. The lever moves up and down, but doesn't change gears. I want to get this problem resolved before I get the bike, in case it is going to be expensive to fix.





The guy who owns the bike reckons it is due to either the shaft (A) being bent or the bearings in the joints (B ) being a bit too worn. I've noticed that the sprocket that C rotates has a little movement - it leads directly into the bike and slides back and forward about 1mm.

If anyone has and idea what this problem could be, and the best way to address it, I would appreciate any advice.

[Semi]

what exactly happens when you try to change gears? Does the lever move and not do anything, or does it get stuck? Is it when changing up down or both?

[huboola]

Th begin with, it changes gear fine, but some time in the first 5 minutes of riding it stops responding. The lever still moves the same amount but there is no change, and it just feels like it is sliding back and forth rather then changing the gears (like no clicking or resistance). The lever itself doesnt get stuck, just stops having an effect on the gear. I think it happens both when changing up and down. I've had it stop responding in both first and neutral.

Thanks for the quick reply.

[druu]

Part C should NOT move at all on the shaft. Part B shouldn't have a rip in the boot, the pivot is probably munted. A bent part A shouldn't affect this too much but make sure it's adjusted correctly to allow you to preload the lever.

[Mattis]

My guess would be that the teeth on part C are worn down and this is causing it the slip on the gear selector shaft. Alternatively the teeth on the gear selector itself can also be stripped. This will mean that when you try to engage gears by moving the gear lever it doesn't give positive drive to the gear selector shaft via part C due to the slippage.

I have seen this happen on a couple of dirt bikes a few times. Usually you can get away with re-cutting the teeth/spline on both the shaft and part C with a hacksaw blade and filing a bit off the edge of the gap between the jaws of part C so that it can tighten more on the gear selector shaft. It depends how far stripped they are though.

It could also be that the thread in part C where the bolt goes through has been stripped and thus it isn't tight enough to engage the gear selector shaft. If that is the case you could re-cut the thread with a tap kit.

The ball joints on part B could also have excessive wear/slop but that generally wouldn't be enough to stop the engaging/disengaging of gears, it will just cause some excessive freeplay in the lever/pedal. You can sometimes get enough adjustment out of the threads on the end to help this.

Make sure it is definitely a gear linkage issue and not the gearbox giving up the ghost though, the linkage stuff is pretty cheap, reconditioning a g/box generally isn't.

[Desmo]

Huboola.
Your avatar give me the heebie jeebies.