More electrical woes

[Snails]

My rear bulb on my Lui keeps blowing.

Ive taken a multimeter reading and I don't see it going above 10v at any point (its 12 v ignition and lighting)
It blows when the engine is running and the scooter on its stand
The bulb tends to blow when its running with the throttle fully open and the engine starting to scream rather than ticking over
The front bulb will blow too but not as easily

Suggestions on possible causes and actions please.

Thoughts in my head are
1. Shorting?
2. I'm not reading multimeter correctly
3. Its spiking but so briefly I cant see it on the multimeter.

[ForemanBob]

Depends.....

Shorting I'd doubt, but possible

When scoot revving nuts off... voltage coming from Stator to Regulator will be at its maximum

Multimeters on AC are pretty blunt tools... good on DC volts...

I would suspect....

1) Poor earth between your regulator and the frame (Check that you have continuity between regulator metal body and the earth point for rear light)
if not regulator thinks its putting out 12v in relation to its earth... your lamp unit could see this as 50v relative to its earth
2) Faulty regulator

[Snails]

Ah, thats a good point about the earth at the rear light as I dont have one! That could explain why its the rear bulb thats blowing?

Where would the best place be for me to take an earth from? Any ideas

[garry inglis]

solder a wire to the side of the bulb holder andback through the hole following the pink and black and find an earthing point bolt

[ForemanBob]

Just make sure with your multimeter on continuity test mode that the earth you install buzzes through to your maghousing and your regulator body.

The earth leads normally run from Mag to frame to regulator to rear light...

Good luck