Hi, not much help with the cover sorry but first thing i'd be doing is pulling the mag flywheel off & [i think] you'll find a sheared off key. If it 'is' then use a holding tool to hold it solidly against the footrest [or something] & swing on the nut with a half inch breaker bar. Maybe overdoing it but--Bought my "83K 490 off ebay & came "Pre Sheared" un-beknown to me damn it, & first kick, you guessed it, she kicked back 'so hard' it took a tooth of the idler gear & bent a tooth on the kick start gear--clutch small gear survived luckily. First thing i did was pull the flywheel & wished i'd done it before trying to start it. guy said [after the event lol] he'd just changed the stator & run it before crating up. Sorry--long story getting longer--bottom line is please be careful & learn from 'my' mistakes. Cheers.