At the Festival of Fives at Seneca Rocks, we hold a "headlight shoot-out." This event is not scientific. It only does one thing, which is show how inadequate the stock tungsten headlamp is in the BMW motorcycle. The various arrangements ranged from stock headlamp, to jamming a high-output halogen bulb into the stock reflector, to using a h4 reflector with a high-buck/high output bulb. But don't take my word for it.
Here is what 5United member Bradley Barrus had to say: "I recently upgraded my stock headlamp to the H4 55/60w and it makes a world of difference! A sound investment in safety."
The general consensus is that an upgrade from a stock 40/45W tungsten bulb 55/60W H4 halogen is easily doable and will not overtax the stock electrical system. Some modification is necessary and easily accomplished by buying an H4 Conversion kit from EuroTech for around $70 (PN 63 10 106 for the H4 headlight, lens, and reflector). There has been some discussion on the list about upgrading to more powerful lightbulbs. The feeling seems to be that this should only be done with an upgraded charging system, especially if you do a lot of short, around-town trips, where you don't get the RPMs up long enough to recharge the battery, and/or you are running other electrical accessories such as electrically-heated vests etc.
Here are list threads about what other members had to say about the conversion and their choice of specific H4 lightbulbs:
Question: I was hoping someone out there in this cyber-world has converted their standard headlamp into a halogen on a 75/5, and could tell me what is involved. Is there a simple bulb replacement, or do I need to go and rewire etc.?
Response: With the aid of careful measurement, an old bulb base and some heavy wire and solder I made an adapter for the H4, and have been very pleased for years. The standard H4 (55/60) draws about the same current as the standard bulb and does not need any wiring changes. I understand that you can buy conversion kits if you are not as cheap as me.
I also believe that you can buy halogen bulbs with the old base but do not know the number. If you want to run a 100 watt halogen then there has been some debate about rewiring. General opinion seems to be that it will work, but my feelings are that you should wire in relays to prevent the switch life being shortened and to reduce voltage drop in the wires.
For those of you who actually ride their Slash 5's at night and want to upgrade from the current Helen Keller/Stevie Wonder lighting system supplied as stock on your Slash 5, read further. First, if you don't have the H4 headlight set up, call Chris at EuroTech and get one. I believe that the Eurotech price list has this conversion at about $70 - cheap for being able to see what is in front of you.
Now, as far as headlight bulbs, I am forwarding below a post from my friend Jan Cutler (formerly of Reno BMW) concerning some new headlight bulbs sold by a company named PIAA. PIAA auxiliary lights have been the standard of the long distance rider for sometime now, along with special headlight bulbs that required fairly heavy duty charging systems. I have used both the auxiliary lights and the older series super wattage headlights for some time now on my K-Bikes and love them. You cannot imagine what riding through the dead of night in the desert filled with cows and no fences is like with 65 watts compared to 300 watts.
PIAA has now developed a set of bulbs that produce very high wattages with the equivalent draw of much more standard bulbs that our meager charging systems can handle. Its my opinion that the charging systems and headlight wiring can handle these bulbs with an additional ground wire that runs directly from the headlight to the frame, a pretty easy addition. The improvement in your ability to drive with confidence at night will skyrocket with one of the bulbs.
Response: PIAA has just announced a Super White H-4, 60/55w that has the output of 110/100w. This is just the ticket for the older overburdened Boxer boys that aren't daring enough to try the other one. On my bike, the difference with the Super White is notable over the Phillips 100/90.
The latter costs $15, so bulb life will determine whether the Super Whites are cost effective.
On the Airheads list, Greg asked about where to get the Philips 100W/45W H4 halogen headlamp bulb. I responded to him privately that CarQuest auto parts dealerships used to be able to get them. Last night I thought that I would dig out a box so that I could provide him with the proper part number, and made a few interesting discoveries:
It may be worth you checking before pitching a bulb.
Question: A while back, I asked about a lead on a ceramic, or other high temperature female socket for an H4 bulb, but got no info except a recommendation for PIAA bulbs. Any other thoughts?
Response: The /5 headlamp socket is made of a higher-temperature resisting material like bakelite, rather than the plastic of later bikes. Several of my /6 or /7 riding friends who run the 100 watt H4's now run these /5 sockets; part # 63 12 8 650 145. I bought a couple about three months ago from the local dealer. Conclusion: The stock 45 watt tungsten headlight set-up leaves a lot to be desired. You may want to consider upgrading to the optional H4 halogen set-up with different bulb variations.