CL77 Sealed Beam Headlight Alternative

Seadog · Post by **Seadog** » Fri Mar 23, 2018 12:40 pm

cknight wrote:The CB72/77 headlamps are 162mm (6-3/8"). Regards, Chase

This thread is a bit old, I know.

Chase, I’m a little confused by this. I measured my headlamp and it’s 6-1/2” O.D. Is O.D. not the correct measuring point?

cknight · Post by **cknight** » Fri Mar 23, 2018 7:31 pm

I found that dimension in a Candlepower Inc. catalog. I believe (that's one step above "I guess") that it's based on where the lamp indexes in the headlight rim. All of the headlights I have, including a Candlepower H4 conversion, measure right at 6-1/2" actual OD. Need to find an SAE standard headlight diameter measuring explanation and chart.... Regards, Chase

G-Man · Post by **G-Man** » Sat Mar 24, 2018 3:19 am

Chase

I'm glad someone else is confused about this stuff. I purchased a little BSA Beagle basket case (I felt sorry for it) and the books say that the headlight is 4 1/2".

Parts are harder to get than early Honda stuff so I bought a 4 1/2" complete modern light off eBay and that turned out to be 4". I bought a couple of other rims claiming to be 4 1/2 inches and they were 4 3/4". It's a nightmare. A Honda C50 headlamp reflector is the right size but the matching rim is too large. It's crazy!

If you find where to measure these things, please let us know.

G

cknight wrote:I found that dimension in a Candlepower Inc. catalog. I believe (that's one step above "I guess") that it's based on where the lamp indexes in the headlight rim. All of the headlights I have, including a Candlepower H4 conversion, measure right at 6-1/2" actual OD. Need to find an SAE standard headlight diameter measuring explanation and chart.... Regards, Chase

Seadog · Post by **Seadog** » Sat Mar 24, 2018 8:05 am

See what you guys can glean from this: https://law.resource.org/pub/us/cfr/ibr ... .1985.html

According to that source, on a 178mm (7") headlight, for example, nothing is actually 178mm in diameter. The "Minimum Diameter Inside" is 178.040.

I'm just as confused as I was before.

cknight · Post by **cknight** » Sat Mar 24, 2018 2:13 pm

Fascinating.. Appears that our CB72/77's have an I B type headlamp, where the maximum diameter of the lamp that's adjacent to the seating plane (the J dimension, where it contacts the ring) is 162mm, or 6.380". The C dimension is the overall outside diameter, and I'm not having any success finding that obviously larger specification. Regards, Chase

Seadog · Post by **Seadog** » Sun Mar 25, 2018 10:25 am

That helps; thank you, Chase. I've ordered a 6⅜" H4 headlamp from Everett Powersports. Another very kind forum member has sent me photos of his CB77 with that particular headlamp installed and it did, indeed, fit. That saves me from having to retrofit an H4 bulb socket onto an original sealed beam lamp. I've done it before and it's not a difficult job, but finding the H4 socket is not easy and they're not cheap.

cknight wrote:Fascinating.. Appears that our CB72/77's have an I B type headlamp, where the maximum diameter of the lamp that's adjacent to the seating plane (the J dimension, where it contacts the ring) is 162mm, or 6.380". The C dimension is the overall outside diameter, and I'm not having any success finding that obviously larger specification. Regards, Chase