Here is my voltmeter. Waiting at the first traffic light, I hold my hand in front of the headlamp, rev the engine to detect whether the lamp's output increases or not. The last 43 years, without exception, there has been charging. Now, could there be overcharging? Possibly, but when I did not have bulbs blown recently and there has been no need to refill the battery too frequently, all is well. Overcharging usually does not start all of a sudden. So when servicing your bike every 3000 km, a simple DMM is all what it takes to check. Turns out I never needed a voltmeter and Honda was right judging we wouldn't need one. There's an advantage in not having a voltmeter. You can keep your eyes on the road. A nice example of 'less is more'. Besides, why would I waist good money on ugly Chinese junk that will make my valuable bike look cheap?
Now an oil temp indicator can be useful. Let me first sidestep to an acceptable voltage indicator Pewe has shown occasionaly, one that can nicely be tucked away between the gauges and will not spoil the looks of your classic. Showing changing colors by leds, it's the only one I'd consider. It's modest, intuitive and - last but not least - can be monitored from the corner of your eyes. Something similar would be nice as an oil temp indicator. I would suggest three color codes: blue = oil has not really warmed up yet, orange = approaching limit, red = too hot. Extinct would indicate oil temp is at working temperature, meaning not too hot, not too cold. Any of you Led adepts think you can make one?
