H4 Headlight Questions

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ptourin

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Jul 18, 2009
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I'd like to find out who knows what about H4 headlights. I've seen a lot of info here and there in different threads on different forums, but it'd be nice to collect some info here in one place.

My '75 Mk III came with a flat Hella H4 light (no city light) - I don't believe it's available anymore. It works well with the stock bike handlebar switches - of course, in the first key position there's nothing lit - I'm thinking about rewiring so that first position lights a city light, for visibility. My old Volvo 1800ES has Cibie H4 lights (with the city light) that would fit in the Norton headlight shell - but again, I don't think these are available new anymore.

Susquehanna Motorsports has 7" Hella H4 dome lights - the ones here are all Euro pattern:

http://www.rallylights.com/detail.aspx?ID=487
Hella 7” round Euro domed H4 bulb plus city light

http://www.rallylights.com/detail.aspx?ID=350
Hella 7” round Euro domed H4 bult w/o city light
This is similar to what’s in my bike, except mine is flat, not domed

http://www.rallylights.com/detail.aspx?ID=136
Hella 7” round DOT approved domed H4 bult w/o city lights
CAUTION: I read that these lights have an air hole that opens them to the atmosphere, and I read a report that dust can get in and cover the silver on the reflector – doesn't sound too nice...

I'd be interested if anyone knows other choices for headlights with a single hi/lo bulb. I'd also like to know if anyone has info about righthand drive pattern vs lefthand drive pattern - I think the ones above are righthand (so OK in the US), and if anyone has any info about whether the standard car lights are OK for cycles - I'm not sure if H4 lights built for cycles are any more rugged than those for cars.

Also interested to hear about possible charging issues when you do the switch to the H4 light. Also curious if anyone has run a 12v line up to the headlight shell for only the headlight and switched the light with a small relay - I did this on my 1800ES and it made the H4 headlight installation a lot more solid. This is pretty easy to wire - I'm just not sure if it's worth the effort on a bike, where the wiring lengths are a lot shorter than in a car.

Peter
 
ptourin said:
Also curious if anyone has run a 12v line up to the headlight shell for only the headlight and switched the light with a small relay
Peter
Click to expand...

That question guarantees you didn't search the forum first. :mrgreen:
 
I saw a couple of threads that talked about it, but nothing that showed a wiring diagram and said "this worked great". We have a wrench night tonight at the shop - we'll talk it over a bit, maybe I can come up with a diagram.
 
swooshdave said:
ptourin said:
Also curious if anyone has run a 12v line up to the headlight shell for only the headlight and switched the light with a small relay
Peter
Click to expand...

That question guarantees you didn't search the forum first. :mrgreen:
Click to expand...


Hmm :shock:
 
BOSCH H4 Headlight + 2 micro relays (one for HI, one for LO) + 55/60 Halogene bulb, connected directly to battery with 15 or 20 amp fuse.

Works great!
 
Yeah, I found that Stern site last night, and that is the Cibie unit on my Volvo - I pulled one out and checked, it's a good fit in the MkIII headlight. More expensive of course - about $75 for the city light one instead of $45 for the Hella. The vintage car people seem to prefer the Cibies over the Hellas for some reason - there are several car threads that compare the 2 brands. I wired my Volvo with relays and it was a giant improvement - I'm not so sure if it'd make that much of a difference on the MkIII since the wire runs are so much shorter. But it's easy enough to try...

> 2 micro relays (one for HI, one for LO) + 55/60 Halogen bulb, connected directly to battery with 15 or 20 amp fuse <

Yes, I drew up one wiring diagram that did it this way. You can also do only 1 SPST relay. You disconnect the line from the pilot/headlight switch to the hi/lo switch and connect the headlight wire from the pilot/headlight switch the 12v side to the coil 85 terminal - 86 goes to ground. So when you switch from pilot to headlight, the relay kicks in. The 30 terminal goes to 12V from the battery via the fuse, the 87 terminal goes to the hi/lo switch. So the hi/lo switch works like it always does, except it's fed by a heavy wire directly from the battery instead of the stock wiring.

Hope I said that so it's clear...

Peter
 
ptourin said:
Yes, I drew up one wiring diagram that did it this way. You can also do only 1 SPST relay. You disconnect the line from the pilot/headlight switch to the hi/lo switch and connect the headlight wire from the pilot/headlight switch the 12v side to the coil 85 terminal - 86 goes to ground. So when you switch from pilot to headlight, the relay kicks in. The 30 terminal goes to 12V from the battery via the fuse, the 87 terminal goes to the hi/lo switch. So the hi/lo switch works like it always does, except it's fed by a heavy wire directly from the battery instead of the stock wiring.

Hope I said that so it's clear...

Peter
Click to expand...

I couldn't figure out how to do it with the SPST relay. I used a SPDT relay and it worked in testing but when I put a bulb on the circuit it wouldn't.

Can you share a diagram?
 
Bill G said:
If by "city light" you mean "parking light" you can still get the Cibie unit.
Look at the 4th picture down. I bought 2 of these this spring. Very nice.
http://www.danielsternlighting.com/prod ... ducts.html

In looking down the lamps available I see they have

H4 halogen bulbs on P45t base
Upgrade your vintage European headlamps to modern-car light levels! These updated halogen bulbs (above left) fit and work correctly in all 1950's through 1980's European high/low beam headlamps originally equipped with tungsten R2 bulbs (above right). Light output is much higher, life is much longer.

45/40W (original tungsten wattage) Narva: $11/ea

60/55W (standard halogen wattage)Narva: $14/ea

100/90W Narva: $20/ea

130/100W Narva: $22/ea

This is cool because if you don't need a large upgrade that may stress the existing wiring you can opt for 45/40W lamp and leave everything else as is.
OldBritts offers a Halogen upgrade for the current city light however when I tried to order they were out of stock and not sure how long before they get more.

Bob
Click to expand...
 
Peter,

The point of using relays to apply power to the headlight filaments is to avoid passing the 5 A of bulb current through the ignition switch and handlebar switch circuits. Thus the only sensible way to use them is to mount two SPST (or DPST) relays, each dedicated to the hi-beam and low-beam filaments, respectively. In this context, your second paragraph would defeat the value of using relays. The heavy relay contacts should be all that stand between the battery and the filaments, with the exception of a 10A fuse, if you choose to use one. Attach the filament to the normally-open contact, and the "hot" battery lead to the relay wiper (or the other way round, it really doesn't matter). For the high-beam circuit, connect the exiter coil to the output of the high-beam switch (blue-white); for the low-beam circuit, use the blue-red wire. Some relays have diode protection on their exciter coil and are polarity-sensitive; you'll have to check it out. Usually, the exiter tabs float, and you can pick the tab to be grounded. For best results use 14 gauge (diameter 0.064") wire for powering the filaments, but certainly nothing less than 18 gauge. The exiter coils only draw a few milliamps, so no special wiring is needed.

You'll be impressed at the improvement in headlight intensity.
 
Thanks Rick - when I was sketching out the single-relay diagram I was only thinking of getting a heavy-gauge wire up into the headlight enclosure and bypassing the ignition switch. You're absolutely right, no way to dodge the 2 relays if you also want to bypass the handlebar switches.

Now I suppose I've gotta start looking at current draw issues and see what I changes I can do without updating the stator and v-reg...

While thinking about the headlight, I've gotten interested in the LED taillight mods - wanting something back there that people can see, if I'm going to put a lotta miles on the bike. I've seen a lot of threads on LED taillight and turn light mods - seems that it's pretty expensive, and some discussion about whether the gain is worth the cost.

Peter
 
The point of using relays to apply power to the headlight filaments is to avoid passing the 5 A of bulb current through the ignition switch and handlebar switch circuits. Thus the only sensible way to use them is to mount two SPST (or DPST) relays, each dedicated to the hi-beam and low-beam filaments, respectively. In this context, your second paragraph would defeat the value of using relays. The heavy relay contacts should be all that stand between the battery and the filaments, with the exception of a 10A fuse, if you choose to use one. Attach the filament to the normally-open contact, and the "hot" battery lead to the relay wiper (or the other way round, it really doesn't matter). For the high-beam circuit, connect the exiter coil to the output of the high-beam switch (blue-white); for the low-beam circuit, use the blue-red wire. Some relays have diode protection on their exciter coil and are polarity-sensitive; you'll have to check it out. Usually, the exiter tabs float, and you can pick the tab to be grounded. For best results use 14 gauge (diameter 0.064") wire for powering the filaments, but certainly nothing less than 18 gauge. The exiter coils only draw a few milliamps, so no special wiring is needed. You'll be impressed at the improvement in headlight intensity. Rick
Click to expand...

I did Ms Peel like Rick says and sure keeps bar switch a lot cooler running.
Check audio and electronic catalogs for the half size 30 amp relays. I had room for 3. 3rd one for long range pencil beams that functioned when hi beam on
so could dip extra brights for on coming.
H4 Headlight Questions


hobot
 
Hobot,

OK, your headlight shell interior looks a whole lot more sanitary than mine. I kept the same connector scheme of the original Mk3 harness (there ae nine connectors), and it's really crowded in there; I had to struggle to close it up. Four of the connectors are associated with the handlebar switches, and need to stay, but two are really not needed (I'll use direct connection instead), and eliminating them would free up some volume.

Rick
 
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