Anyone looking for an alternative for the illusive original sealed beam unit used on CT1, CT3, RT1 and a few others models could look at the unit for a 1978 DT175MX supplied by Yambits.
I know there are other solutions, such as removing the lamp from the original sealed unit and replacing with a LED or H4 lamp, I have tried both methods and they are fine, althought the beam is far from perfect.
Just thought I'd offer up this information because I've just swapped out my unit on my CT1-B for this unit and it looks and functions fine.
It currently costs £17.99 from yambits and comes with spare headlamp bulb and sidelight bulb.
Simply unclip from the supplied surround and clip straight into the orginal chrome surround.
Replaceable lamp for all of you out there that haven't added a voltage regulator.
Other 5 3/4" units are available, just thought this was good value.
yambits.co.uk/dt175mx-headlight-unit-p-5052.html
 

The only possible problem is that the focus is likely to be biased to the left .
Not a problem for you and I , who drive on the correct side of the road , but may present issues
for our Stateside members .

I have a question regarding the reflector bowl on a sealed beam: Is that Chrome plated metal, or glass mirror?

If metal, when the time comes for replacement, I think I could modify the one on my DT125B to receive an H4 socket. If glass: No way I would consider trying.

Seeing as I intend to keep the DT125B for my remaining years, I am looking for a long term solution.

Thanks for any input.

V-man
From the land of those that ride on the wrong side of the road

I squeezed a 6V H4 bulb into my CT-1 sealed beam a while back. Post # 15 has pics. It's not a good beam for night riding, but I only use it for daytime visibility. Also put a voltage regulator on, which is why the old bulb blew. The bike never had one.

www.yamaha-enduros.com/index.php/forums/...rging-issue?start=10

Thanks Tom.

I think both beams work on the bike I'm buying... but the time will come one or both won't.

V-man

Vinduroman, here's a couple of threads showing a few methods of replacing a lamp in a sealed unit, there are also more post on the forum if you search.
I found a 6 volt LED lamp with high and low beam that fitted without the need to enlarge the hole and the beam spread was better than the H4 lamp.
www.yamaha-enduros.com/index.php/forums/...6-rt1-headlight-bulb
yamaha-enduros.com/index.php/forum/resto...eam-headlight#137300

Thanks Pete.

I shall hit those links.

Of course, my new-to-me bike being of the AT/DT line w/starters, it will be a 12v system, but I'm sure any tips/techniques will apply to what I need to do, as well.

V-man

I've tried and seen a few "glue a bulb" methods of trying to repair a sealed beam headlight.  I've never seen one that provided any sort of usable high and low beam...  getting both of the filaments precisely located in the reflector is not as easy as it sounds.  I do appreciate the honesty of responses to this thread that say this. 

It's hard to understand even trying it on most Enduro models with the 5 3/4" units...  there are just so many options to replace those with a safe, legal, bulb at not too high an expense.  If nothing else, pop in a common 12 v round auto sealed beam.  With a couple of retaining clips, you're done.  There are old threads here and people I've ridden with who swear by using a 12v headlight... there's evidence no regulator is needed on the older bikes if you do.  They also report a good headlight...  possibly dimmer at idle but good enough to ride with at night if needed. 

Or I really love this Yambits option Pete posted!  Even if beam biased (hard to tell from pic) it would be better than every "repair" I've seen or tried.

On a 12v 125 with smaller sealed beam, or something with an oddball headlight like my 17w series DT50's, attempted repair starts to make more sense. 

Vinduroman, I think I have a NOS "replaceable bulb" headlight reflector from an early AT1.  I don't have the bulb holder but they can be found.  Not sure if it would fit the later DT125 but it might.  Or possibly check out a place called "Dr. ATV".  They have lots of parts for the little Honda 50's and 70's that used a smaller headlight...  Maybe a headlight for one of those would fit a 125?  They say they are about 5" diameter and they have both 6v and 12v bulbs.  Here's one for the CT70 but I think they have others for different models...  scroll down the page for bulb selection.  dratv.com/newoffroheas.html

Mark:

Thanks for your input.

As for diameter of the headlamp in a DT125B, I won't know until I get it back to the house and can measure it. I have "assumed" the headlight diameter will be the same as Wild Child's AT3 was, but I don't know.

I was under the impression that the AT series had unique diameters hence the AT-1 bowl w/bulb conversion I performed on Wild Child's AT3 after the last functioning beam of the OEM sealed beam unit burned out.

I hope it's a size in which I can readily find a reasonably priced replacement when the time comes for a new headlamp.

I intend to stack thousands of miles on this bike over the coming years that I am still physically able to ride. (Decade+ I hope!) Thus, I think it's highly likely that I'll need a headlamp in the future.

V-man

It's possible that the RD125 and RD200 headlight might fit, but strongly recommend checking and double checking measurements first (I can assist with this if needed)! Looking at the YHA number stamped on the underside of the bucket will also help.

Looks like some of the US bikes around that era had those really weird inner rings! 

CMSNL have some new sealed beam lenses.

If you want a lens with replaceable bulb option and with the correct beam alignment, then it might be worth checking places like ebay.fr and ebay.de - mainland Europe drive on the wrong side of the road as well!