Electrickery

[Jazzy]

Whats the correct way to test a regulator as I,m blowing speedo bulbs.

if I put a multi meter anywhere near the wiring when its running the meter goes loopy before I touch anything.

[mick1]

You may have a faulty regulator and some of the cheap digital meters can't compensate for the rapid change in voltage. either get a decent quality meter or try an analogue one (they usually have a damper on the needle).

[Monty]

Assuming its 12 volts.
Set your meter to AC volts, black to a good earth red to say the back of the headlight bulb. Start the scooter and turn on the lights at tickover it should be below 12 volts, ignore any .00 readings, most flicker a bit on tickover. increase the revs your headlight should get brighter and your meter should rise to say 13 but not a lot higher if the regulator is doing its stuff if it going up to 20 plus its buggered and you will loose bulbs.
If its only the speedo bulb check the earth, dont rely on the speedo to earth it. strip some wire and wrap it round the bulb holder and push it in the speedo then earth the other end. you can solder it on the bulb holder if it works

[Jazzy]

cheers guys,

Monty I think your on the money mate, used to have separate earth on speedo bulb but has got lost over time.

And Mick, yes it is a cheepo meter