Gearbox troubles

Hey everyone

Just got back from a ride and it wasn't such a pleasant one. I'm having some serious trouble changing some gears. To be more specific, it's upshifting from 2nd->3rd and 3rd->4th, when the gear lever just seems to be absolutely stuck, as if I've reached 6th and there's no upper gear to go into. Downshifting everything's just fine (I guess it wants me to go slower.. ).

It started about 3, maybe 4 days ago and at first it was just a simple difficulty, and it only happened from 3rd->4th. Now it's spread !!

Thing is, I don't know the first thing about gearboxes..

So? Any thoughts on the matter? Oh, btw, the bike's an '00 curvy S, with some 18k miles on it. Oil changed about 2k miles ago and other stuff taken care of (but the oil is the only thing I can think of that relates to the gearbox)

the chain tention also seriously affects gear changes worth a butchers

[Biker Biggles]

Check chain adjustment,
Check oil level,
Check clutch adjustment(properly including the worm drive by front sprocket)
Check gear lever where it pivots.This can get corroded and cause all sorts of trouble.
While you are doing that make sure the linkage is all OK and no one has altered it to cause lack of upshifting movement.
If all those are OK get someone qualified to have a look.

have you tried clutchless upshifting? ie where you put upward pressure on the gear selector as the rev's rise, then when you want to change just blip the throttle off then back on a bit. if this works fine then you can rule any clutch problems out.
The only other thing i can think of is worn/broken gear teeth or selector forks jamming, but probably not something you could check/replace yourself.

hope this helps

Cheers

[SoulKiss]

Maybe the gear lever IS stuck.

Have you tried removing it and adding some grease.

Had very similar on my Z750

[yorkie_chris]

If gear lever is not returning down properly, far enough that the ratchet catches the next gear all you are doing is selecting the same gear again.
But this normally moves up a little way just does nothing.

Is your clutch otherwise happy? Nice and progressive bite? Or is it grabby, jerky or generally shagged?

Well, I've tried clutchless shifting, and it works with no problems (btw, thanks for the tip on how to; it's very smooth). I don't know if the gear lever is the problem, 'cause when I do it with no clutch it moves just fine. Although it "feels" like it should be something wrong with the lever, as if it would be stuck in position.
The clutch is also fine, no jerkyness of any kind. I'm thinking maybe there's wrong with it though. Maybe it fails to disengage the engine somehow. I just don't see how it would be so specifically linked to just these 2 positions (2->3 & 3->4)..

I'll try removing the gear lever and adding some grease to it, as SK said. If that does not work, I'll watch how it returns to position. Maybe there's some foreign body that blocks it somehow..

And if the gear lever is not the problem, I'll move on up to the clutch for further inspection..

I know some one mentioned checking the oil level before but just want to make sure you know. If the oil level is too high that can also cause difficuly shifting as well as finding neutral

I did check the oil yesterday and it was close to the full mark (ran the bike for a couple of minutes, stopped it, then brought it up straight and left it to sink for a minute or so). Tthe oil is relatively fresh (2k miles)