Gearbox problem - BMW R80

I am having trouble changing gears on my 1989 BMW R80. 1st, 2nd and 3rd
work OK but when I try to change to 4th, I get a false neutral.

Anyone have any ideas as to what could be wrong?

thanks,
Paul

 

The gearbox.

 

I can't believe you'd give information like that away for free.

SS.

 

Well, it's Christmas.

 

Sorry to hear that Paul,
Air-head gear boxes are not an easy fix.

Check the linkage first to make sure you're getting the full throw.

If it's not just your shifter linkage, it's a job for the shop.

Best of luck,
MadDog
R75/5 Forever!

 

http://homepage.sunrise.ch/mysunrise/joerg.hau/mot/gearbox.htm depicts
Germany's revenge for national humiliation in WW2...

Excessive axial play in one of the transmission shafts is the usual
cause of airhead shifting problems.

Even if the ratcheting shifter pawl works right and the two shifter
plates
move together like tango dancers in love and the detent wheel holds the
plates in the nominal position for any given gear tryst, a shy slotted
gear may be able to move away from the incoming gear's urgent dogs.

Don't ask how I know about uncooperative gears avoiding contact with
each other...

Another problem may be a bent shifter fork from merciless attempts to
change gears...

Joerg also mentions pawls and springs that break, radial ball bearings
that are not designed for axial shock loads, and some part that may
need to be soldered together, once the gearbox's innards are exposed to
the harsh light of the gewerkenshoppe...