nighthawk750.freeforums.org

I posted about a month ago trying to figure out what was wrong with my brother's CB750 that was stuck in gear. Today I finally got my hands on the bike and started pulling it apart. I still have no clue as to how a simple get off caused this but looks like the culprits of the problem are a broken pawl plunger on the drum shifter and then more importantly the shift drum set itself is busted on the end. Following the Cylmer manual to replace the shift drum set I have to pretty much pull the motor out of the bike which includes removing the cylinder head, pistons, clutch, oil pump, flywheel, and oil pan. I'm doubting there is but was hoping someone might know a trick to get in there and release the shift drum without all this other tear down. So, if anyone has any ideas I'd be eternally grateful.
TIA

Pics of the damage...