Gpz uni only got 1 gear

[pluto]

After laying this bike up at least 2 years ago I have got to the point in my rebuild where I could start the thing up, it fired and sounds lovely, a bit smokey from where I oiled the bores for storage but to be expected.
Problem I have is gearbox - clutch works and allows 1st gear to be selected, it pulls off smoothly - then wont change up the 'box. I popped off the sprocket side cover and the gear mechanism cover but cant see anything unusual. It worked fine before and gearbox was full of oil so no corrosion possible.
Any ideas before I have to start pulling it to bits again to take sump off and clutch out?
Cheers
Dave

[Pigford]

You were actually riding the bike - YES

Remember the Kawasaki safety feature - (or easy NEUTRAL selector function) - bike will only select 2nd when moving.

If the bike was in motion, perhaps the little bearings in the gear lay shaft (or wherever) are a bit sticky? Try an oil change

[pluto]

Yes - sort of but in the confines of the workshop! My B2 will slip in to second as soon as the back wheel is turning and the unitrak was having none of it - something definitely stuck somewhere. Oil change will happen as I've just emptied the sump taking the gear selector cover off. What is it in the gearbox that stops you going directly in to second?
Dave

[Pigford]

There are small bearings in the gear shaft - can't remember which one (main or lay?) which stop the gear cog moving until they are turning and centrifugal (centripetal) force makes them "get out the way" and the cog can shift

[zed1015]

There are 3 small ball bearings that prevent the gear from sliding along its shaft and they only release under centrifugal force, hence the need for the bike to be rolling before second can be engaged.
They can be removed but the engine needs to be split to disassemble the cluster.

[pluto]

Thanks to you both - I will put it back together, change the oil and run it up as fast as possible on the centre stand with the wheel in the air, and see if that frees the bearings off.
If not engine out again I suppose.

[pluto]

An update - I took it up to 6-7000 rpm with the bike in first and the back wheel whizzing round and tried to select 2nd, after a few disheartening attempts it decided to stop misbehaving and jumped in to second. It now works just as it should.
Thanks again
Dave

[Pigford]

RESULT