Just put the 100w90 bulb in my bike. Gage used to read 12.5 to almost 13 volts whole time I've owned it 45,000 miles. Now it is at 12 volts Max and after a restart it was 10 till I reved it. The wires don't seam to get hot but I'm wondering if this will be hard on the stater and battery. Should I pull this bulb. Just hoping for better light after rideing with guys with daymakers I felt like I was in the stone ages.

 

I would check voltage at the battery terminals with a multi meter rather than rely on the dash voltmeter. Then, if you're so inclined, calibrate the voltmeter. There was a thread in here about a month ago, but the procedure might also be covered in the factory service manual. ..I dunno for certain.

I put a 90/130 watt H4 bulb in mine, and when I use the high beam, it also pulls down a bit..When I trigger the 100 watt landing light bulbs in the spotlights, it pulls down more. I don't sweat it cuz I don't turn for too long.

 

What should the battery be not running

 

I would say a healthy battery would be in the 13.5 vlot and up range. That said, many folks have reported adequate or better starting performance at a bit under 13 bolts.

I'll qualify that by saying that the measurement is made with a high quality multimeter. ..I wouldn't rely on the OE voltmeter. ..at least until after I calibrated it and confirmed that I could rely on it.

 

13 volts off & 14.2 running real gauge.

High beam doesn't change Gage on bike.

 

You're good

 

These.bulbs will fry the single phase stator's which are in Harley touring till 2003. When the system is maxed out it runs hot and melts the coating. The three phase stator's can be maxed out with out harm, I have learned the hard way