I have a 93 with 35,000 on it. Just got it back from a full service and new tires installed. Left Wednesday on a 250 mile round trip to a work conference. Everything worked great. Temp in the mid 80's. When I parked for the day I noticed a bit of a funky smell, like sulfur a bit maybe? Didn't think too much of it..... Next day the bike wouldn't turn over. I push started it and rode it into the small town near the resort I stayed at. The local moto/atv mechanic tested the battery and said it had a good charge but wouldn't crank the bike, must be a dead cell. He put a new one in, said the system was charging well and I was on my way. Is it that easy? I've read about the dreaded R/R problems. I made it home fine in 90 degree heat, bike started fine when I went to work this morning. Just wanted to make sure I don't need to look further into this.
You can't tell yet. Even if the old battery was dead, RR problems could have caused it. If you have reason to suspect your RR is acting up, the best thing to do is put a voltage meter on it, somewhere you can keep an eye on it while you're riding. Most likely, it's just the battery though. I wouldn't worry about it. 35,000 miles is plenty for 1 battery.
