Rode it to work today. Wouldn't idle properly and check engine light came on. Crap! Got to work and it died as soon as I dropped the throttle.
About 10 V on the battery after it sat for an hour or two! Terminals are tight. Seem to be getting voltage when the engine is revved so it is looking like the battery has given up (I hope that's the issue rather than the charging system). I have put the battery on a slow charge for a few hours and I will let it sit overnight to see if the voltage drops again - I'm thinking it will. The 10V was (surprisingly) enough to start the bike. Rather than capacity going off, I suspect there is one cell shorted.
Damn batteries. You would think they would last longer than 9 years and 163,000 miles! Was hoping for 10 years/200,000 miles.