Motorcycle Repair: honda 1980 Xr80, cbx 1000, rear sprocket

Question
i know you only deal with the CBX-1000, but i really need help on this bike

the chain is coming of the cogs when i get up some speed (3rd gear or higher) i have been searching on the internet for some manuals to look at but none have helped

would you be able to tell me how to tighten the chain or something like that.
or could you put me onto someone that can

much appreciated
          wil

Answer
Check the condition of the chain and the gears.  Also make sure the rear wheel is in the swing arm straight, and lined up with the front wheel.  Ensure not too much play in the rear sprocket, and also that the output shaft of the engine is not bent.

Good luck,  Jan