ZXR750 H1 Jumps out of gear

Hi all, can anybody help with the common causes for a ZXR750 H1 to constantly jump out gear & false neutral.
Cheers

worn gear box worn clutch (too many clutch dumps ) wrong oil are some causes

As you mention false neutrals ...what oil you suing???

I had that issue with my ZXR750 H2, It was a worn selector drum.
I was told the steel used was too soft & that the selector forks rounded off the ramps.

my 94 skips in second but not back to neutral.
has anyone had this fixed and if so how and how much?

Sounds like either worn selector forks or a worn shift drum. More likely the former.

....Sounds like either worn selector forks or a worn shift drum. More likely the former.....

thats it - and both the selector fork and corresponding groove in the shift drum will be worn. Its not often you get one without the other.... Its not hard to fix, but does require splitting the cases to get into the 'box and replace the worn bits.......also a good time to check the gear selector dogs as well, these can also wear and cause the box to jump out of gear....

Yep - you guys are all right !!!! pulled it down & found selector drum very worn. Also selectors & dogs showing some wear. Unfortunately cant buy them anymore. Got a line on a good second hand engine with low Km's - might be worth a look.
Thanks for your help.