battery/charging issue?

gonna try in here too...
'82 Maxim 750 :x
I tinkered with the suspension this morning, then it started fine - from cold, hadn't been started for a few days except a 1 minute run to hear if exhaust was blowing, then jumped on and did around 8/9 miles, stopped to tweek shox - with engine running and twin spots on, did another 2.5 miles to home, stalled it at the back door tried to re-start and the battery was dead!
The starter solenoid was rattling away with not enough power to turn the engine, Put a tester across the battery terminals and it read 18 to 19 volts and climbing.
Tried to start it 30 mins later and the engine turned over but not enough power to start.
Any thoughts anyone?

 

18-19 volts??!!! WOW! By tester do you mean a voltmeter or a battery charger?
Have you checked the alternator brushes?
What voltage are you reading off the battery when the bike is idling? 2,500rpm? You should see static voltage at idle to about 2,500 rpm, then the voltage regulator should kick in and start charging at about 14 volts.

 

If you saw 18v your reg/rec is cooked and not working...you boiled the battery. Bet there's no water left in it...