headlite bulb blows ?

I exchanged my stock headlite with a h4 halogen bulb. Now the bulb keeps burning out. I think it happens at high RPM's. Is there a voltage problem with this setup or is it likely some other coincidental electrical problem?

What size of H4 did you put in? At one point I had tried a 100/130. Way too big, too much draw, think it was 15.8A. And of course it blew the main fuse at 5:00 in the morning leaving work, in the middle of an S-curve! High pucker factor!
Try some fresh fuses and make sure the fuse holders are clean and corrosion free. ATM I am trying out a GE "Nitehawk", about $25 at Cambodian Tire. Seem brighter than the regular 55/60 H4, and supposedly longer life. Good luck!

55/60/h4 With a relay for a fuse.

Make sure it's not a vibration issue...happened to Me,and it took Me about a year to figure that one out.For the longest time,I too thought it was a voltage issue(spiking).I was going through a bulb every ride out,pretty much.I replaced some of the rubber grommets at the headlight bucket and even added some extra rubber to dampen the vibration...all good to go now...haven't blown a bulb since.

(make sure You don't overtighten the mounts on the rubbers.They need to be snug,so You don't compress the rubber,defeating the whole purpose of them dampening)

I would guess that Sandy is on the right track. Vibration in a bike's headlamp is a lot greater than a car. The bulb was designed for a car and not a bike. They DO sell "heavy duty" H4 bulbs that do tend to last longer.

As far as the power consumption, here is how you tell... the headlight is on a 10A fuse if memory serves. Check your fuse box to be sure. DO NOT swap a larger fuse in as this doesn't increase the diameter of the wiring which is really the limiting factor on your headlight circuit. OK... say 10A is the circuit limit. If you have a 130W bulb at 12V, going to high beam will mean 130/12= 10.83A draw. This is TOOOO MUCH for a 10A circuit. You really want to keep the draw on the circuit down below is capacity by a couple of Amps... Plus there MAY BE other stuff on the same circuit like running lamps or turn signals. An 80W high beam will draw 6.7 Amps so I would NOT go any larger than that and that high beam is pretty bright.

I think a better solution is to buy one of the "ultra-white" heavy duty car bulbs 60/55 where the white beam on high is supposed to be equivelent to an 80W normal beam. These headlights do seem brighter than a a standard bulb without the associated higher draw. I bought several cheapo 80/55W bulbs from JC Whitney but they are yellow light and very dull. The 80W high beam is actually duller than a 60/55W ultra-white bulb I use. Also, if you are interested in safety, keep in mind that most older bikes have DIM rear bulbs. A modern 1157 will replace the OEM Stanley bulb and the modern tends to have more brightness. You might also rewire the rear turn signals to include two contact (hot) bulb holders and wire in running lights for safety if you operate the bike at night.

Thanks for the great advice guys. I did change my h.light bracket when I went to the halogen bulb, so this could verywell be the problem. I'm still working on restoreing my bike after it sat for 22 years,so I wont know the answer to this right away.I will most certanly buy a heavy dudy bulb and work on vibrations.Thanks again:) WIRDGEORGE: Just thought I'd say that i've read several of your post responces and i think you are beeing very helpfull to a lot of us.Thanks.