H4 light for /5

[fig]

Anyone know which H4 headlight from later bikes will fit a '73 /5? I'd like to upgrade and would like a real Bosch setup (glass lense etc.) rather than aftermarket. I've shopped around ebay but I'm unclear which model/year is the right fit for my bike. Any ideas?

DF

[Rob]

I believe the R65 lens/reflector is a direct replacement.

from snowbum:

The /5 came with a 45/40 watt NON-halogen headlight. It is best to convert to an H4, BMW offered a kit for that. You HAVE TO change the lens too, OR the H4 pattern is spread about and awful. You can rather easily adapt the R65 headlight parts to a /5. Conversion gives vastly better lighting at night, using a 55/60 watt H4 halogen lamp. Later bikes got rid of the clip method of holding the bottom of the headlight chrome ring which sometimes allowed a headlight assembly to fall down. Modification of early chrome rings to avoid loosing the ring, headlight, etc., is a good idea.

http://bmwmotorcycletech.info/models.htm

[fig]

Do you know what year? Max's parts fische lists R65's from 78-85 then also 85-87. There's also GS and LS models. Max sells the kit Snowbum talked about for $585.00

[Rob]

'78 (Europe only) - '84

In '85 they put the 650 engine in the Type 247 frame, which has a larger headlight.

R65LS, R80G/S and R80ST are also donor candidates.

[gocytocis]

I used this in an original Bosch lens/reflector in my '72:
https://store.bobsbmw.com/product/h4-he ... dels-5560w

[fig]

Thanks for the R65 info Rob! Gocytocis that looks like a bargain, only 6 bucks. I think I'll try that first, is there a noticeable improvement?

[Rob]

I used this in an original Bosch lens/reflector in my '72:
https://store.bobsbmw.com/product/h4-he ... dels-5560w

What about Snowbums warning? Did you notice this?

"You HAVE TO change the lens too, OR the H4 pattern is spread about and awful."

[gocytocis]

is there a noticeable improvement?

I have been very pleased with it, both in terms of overall brightness & whiteness of the light.

Regarding the issue of "the H4 pattern is spread about and awful" noted above, I don't ride unlit rural roads at night on my /5 often so I can't comment except to say that I've not noticed a problem, either with shadows or hot-spots. It is certainly a better light spread than a typical aftermarket HID conversion would give, much better.

[gocytocis]

What about Snowbums warning? Did you notice this?
"You HAVE TO change the lens too, OR the H4 pattern is spread about and awful."

I'm not sure what difference the lens would practically make. If anything, surely the reflector would be more critical than the lens(?).

The only dimension that changes once an H4 bulb is installed is the location (only nominally) & orientation of the filaments, which for all practical purposes remain at the 'focus' of the parabolic reflector, so the overall focus of light should not change significantly. Regardless of incandescent or halogen, it's a filament which produces a line of light rather than a discrete point so there's some imprecision built into the system either way. Once the light then hits the lens from the reflector, it's irrelevant whether the source is a regular incandescent bulb or a halogen bulb, it'll refract, for all intents & purposes, identically.

[Major Softie]

While I agree that one would think it would make a bigger difference in reflector than in lens, there are two differences you did not mention.

The incandescent is not "shaded" in the direction of the oncoming traffic the way the H4 is (which could definitely be more lens related).

I believe the filaments do not travel in the same direction (which would seem to be purely reflector related).