voltage spikes?

[mp183]

Last year I had a problem where my 2002 GS burned out my Headlight bulb.
I did not think much of it but before it went the light output was going up and down for about 10 minutes.
Yesterday I started it up and the same thing happened for about a minute and afterwards it stopped.
It was no due to rpm fluctuations.
Bike has been standing a lot over the last two years but has less than 30,000 miles on it
any ideas?
Next time I'll try to get a volt meter on it.

[adidasguy]

Replace the voltage regulator.