I have a Candle Power headlight in my 75. It comes as a replacement lense and reflector, it take H-4 bulbs. I run a 55/60 watt bulb.
Upping the power will find any weak spots in the headlight wiring. Any dirty contacts in the wires or switches will show up quickly. These weak spots have resistance, this extra resistance keeps the light from being as bright as it should and also increases the current draw, this can reduce the current to the battery. This will let the battery go dead.
Leo