Battery discharge

Battery discharge FZR 1000 moin moin Would like to introduce me first here on the board I am the owner of a ́88er FZR 1000 2RG (English model) Since yesterday I have the problem that the battery is pulled off during the ride, so really fast discharge I have the feeling (after 2 km – to the tanks – the battery does not even get the starter to crank through). After about 1/2 hour rest period the battery is again (almost) like new. Is good – Push cake – the same again. Pushing goes perfectly. If someone had any idea and could help me in about. gruss MuH