Topic: Why am I blowing bulbs and not fuses?

[bookah]

So I've been working through all of my electronic gremlins, and I can't figure this out. I'm not blowing any fuses, but I'll blow my head and tail light simultaneously. I have been all over the fuse box with a multimeter, I have continuity for each fuse.

[Dunk]

Voltage and idle and 4000 RPM with lights off/on? Could be high voltage from a regulator or wiring issue.

[bookah]

Idle is around 11.8/9-12 and at 4k is around 14.3. Highest spike I saw was when I went from idle to WO and it hit 15.1

If I dont gradually build up the throttle and just go WO it usually spikes to high 14s and falls back down.

Would a loose connection be to blame? I say this because while testing my battery with a multimeter I have the seat off, and the negative battery cable is ground to frame under the seat using the seat nut to bolt it to frame. When the seat is off the negative is held in place using a bolt but not tightened with a nut, just bolt through negative then through ground hole. Both times I've blown bulbs has been during this scenario.... hmmm...

Maybe the negative cable is losing contact in high rpms then regaining contact...thus blowing the bulbs? Can this happen?

[Mr. Mike]

 Figure out a way to secure the ground cable permanently to the frame and you'll probably be alright. Any arcing in the light/power circuit will most likely just zap it with high current beyond its filament capabilities, especially if your revving it.

[Duke McDukiedook]

+1 on the bad ground.