looking at buying an 81 750 C with 30,000kms. Bike seemed to start and run well but when I went to start it up again after shutting it off for 10 min the battery was dead. The guy said it was a brand new battery. Is this a common problem that will happen with this year and model after 28 years? I like the bike but donĀ“t want to get into too many issues to fix. Is this an easy solve?