I recently had an embarrassing breakdown due to none charging ( roundabout, traffic, people having to push me! ) just before I took it in for the repaint, so I just fitted a spare charged battery for the time being and looked at it when I brought it the short distance home.
Clee had advised me to check the two small two pin plug on the back of the alternator, which I had given a quick roadside check when it died and it seemed to in OK
I have been having charging issues on a old bike and one point I have never really pursued was the need for absolutely clean connections, using a mild acid to clean them and then using dialectric grease ( I had never heard of it and admit just used Vaseline ) anyway I used some neat alloy wheel cleaner sprayed on the connector, then washed in a little water, then WD40 and used a small screwdriver to tighten up the spades and some Vaseline on it, then similar on the alternator male spades but with the acid on a cotton bud.
Hey presto a peak of 14.6 V when off idle, I think there should be some sort of locking tab that may be missing on the connector, and having tidied up my engine loom, wrapping and shrinking that part of the loom I think I had left the weight of the large red lead pulling down on the small two pin connector.
When I have found somewhere to mount it I'm thinking of putting one of these in,
http://www.ebay.co.uk/itm/161270154323? ... EBIDX%3AITWhen you think about engine affected breakdowns, you either lose juice ( so you have a fuel gauge as a minimum)
you overheat ( so you have a temp gauge) loose oil pressure and hence engine damage ( so you have a pressure gauge) so a simple volt meter allows you to keep an eye on charging.
A warning light will usually only tell you when its nearly too late, I had no warning light and ended up flat as a witches tit.