My headlight just started brightening (considerable) when I hit about 3K RPM'S. Bought the bike with a aftermarket chrome voltage regulator so I'm not sure what kind it is. I'm not sure if it's characteristic or if it's something I should look into. Any feedback???

I would check the voltage at the battery at 3000 RPM and see if it's correct.

I have never worked on an 1980 Sportster, but I can give you some ideas in general.

When the battery voltage is low, the headlight is dim. The faster the alternator spins, the more electrical current it produces. At 3000 rpm, it is spining fast enough to produce enought current to keep the headlight bright. Problem is, this seems a bit too high of rpm. Usually just above idle is all that is needed to keep the headlight bright.

Your battery could be getting weak, and needs more current to charge it.
The alternator could be getting weak, needing to spin faster.
The voltage regulator could be creating the same problem.

I would suggest getting it checked out before it leaves you stranded. Unless a bunch of guys with the same bike say it's normal.

Actually the alternator doesn't produce more current but more voltage.Voltage is always there where as current only flows if there is a load.Volts and amps are two different things.

I have never worked on an 1980 Sportster, but I can give you some ideas in general.

When the battery voltage is low, the headlight is dim. The faster the alternator spins, the more electrical current it produces. At 3000 rpm, it is spining fast enough to produce enought current to keep the headlight bright. Problem is, this seems a bit too high of rpm. Usually just above idle is all that is needed to keep the headlight bright.

Your battery could be getting weak, and needs more current to charge it.
The alternator could be getting weak, needing to spin faster.
The voltage regulator could be creating the same problem.

I would suggest getting it checked out before it leaves you stranded. Unless a bunch of guys with the same bike say it's normal.

Nope...I think you're pretty spot-on.....

Check:
static voltage
voltage at idle
voltage at 2000 RPM
voltage at 3000 RPM

Any reading over 14 volts is suspect, and indicates a voltage regulator (rectifier) failure....

Anything below 12.8 v static is a problem, as well....but that's a battery thing.....but COULD be caused by a faulty regulator...

Load test after a full charge is the only sure way to know about the battery......

crospro - higher voltage differential is what allows higher current to flow.

Cantolina - thanks for filling in the numbers, I don't do it enough any more to remember the details.

I'll have to check my voltage readings then. Wanted to make sure it wasn't something characteristic and chase a ghost. Nothing worse than throwing parts.....