Gears grinding when trying to shift up or down

[Seek]

In the BMW's the primary shaft of the gearbox runs at engine speed, while in other bikes it runs at a reduced speed. I've always heard that makes it more difficult to design a clunk free gearchange.

[niall4473]

I think that this discussion has missed the obvious.It sounds as though the clutch might be dragging, a 'clunk' is normal but not grinding noises, however it's easy to check:
Bike on centre-stand.
Select first gear.
Operate clutch.
Press down on kickstart.
After a moment of 'stiction' the clutch should free-off fully without any drag from the engine, if it does not, there is your problem, first port of call then would be to check for excessive free-play on the actuator to pushrod adjustment.
Good Luck.