6" H4 headlight brightness vs 7" H4

[Chuck78]

Last spring, my sealed beam burnt out, so I found a 7" H5 headlight setup from an 81 GS650G. I was amazed at how much brighter it was than my old setup, and brighter than my all of my friends' vintage bikes other than my buddy's 82 KZ650CSR.

Well I had an unfortunate collision with a deer this past weekend at 55 mph that took out my headlight, left turn signal, speedometer, and my kneecap! I rode away without going down, but there was a lot of cosmetic damage to the bike. My beloved H5 lens got destroyed.

Today, I went to the junkyard and got a 7" H4 lens and 55W bulb that fit into my spare bucket and bezel. I also picked up a much cooler looking 6" H4 setup that I think is off of a GS1000 L model. It has a bit of rust on the side that probably won't buff out so well, but I may be able to touch it up with silver paint and clearcoat it and get away with it.

I was wondering, with the same bulb, will the 7" be substantially brighter than the 6" even though they are both H4's with the same bulb? The 7" plastic bucket setup is lighter, an added bonus, but the 6" has much better stylings. My wife's GS550 has a 5 or 6" sealed beam that is the dimmest of all of my friends' bike lights, so maybe that would be a better upgrade for hers? Still, the look of the 6" is awesome, so please advise me of the brightness of the 7" H4 vs the 6" H4. Thanks

 

[Steve]

"H4" is the bulb, not the housing, so either one will be as bright as the other.

Any differences will be in the shape of the reflector and lens arrangement.

Either one of them WILL be better than the sealed beam.

Just so you know, if you switch from one size to the other (does not matter which way you switch), you will also need to change the mounting ears. The two lights use a different offset, so the turn signals that mount to them will not extend straight out.

If you are interested, I have a complete setup that just came off my son's 650L. Chrome 6" housing, trim ring, lens/reflector, bulb, mounting ears. I would have to re-inspect it, but I think it's in pretty good shape. Not quite "showroom perfect", but I would be proud to have it on my bike.

.

 

[Chuck78]

Part of the reason I asked was because the reflector lenses usually have H4 or H5 etc molded into them.

So with the same H4 halogen bulb, is there any standard comparison between a 6" and 7" lens of similar style? I would have figured the DOT had some kind of regulations on these as far as light pattern and intensity.

I just picked up this 6", but as you can see the bezel has a rusted spot on the side, so I still might be interested in that setup you have Steve.