Hello!

I’m struggling to find a replacement bulb for my 1971 CT1. The Koito # is 110-31848.  Does anyone know of an available replacement?

pic for fun

Thanks for the help!

Are you looking for just the bulb or headlight sealed unit 

The bulb that’s in there is a sealed beam.  The glass is in perfect shape.  At first I thought I might be able to pry it apart and replace the bulb, but I don’t think it will come apart. Is there an option for using a replaceable bulb?  I would prefer a set up with replaceable bulbs, but I would take another sealed beam if I could find one for sale. 

  

I did see that, but it doesn’t look it’s the same as what’s on my bike. The headlight has a hook for a spring and a spot for the adjuster. 

I just bought an old '75 TY250 headlight assembly and a 6 volt bulb for my CT1C on EB.

Looks like you will need to do some searching for the original setup.

There's about 200 threads on here on how to replace the original headlight with a 5 3/4" replacement... sealed beam or replaceable bulb... using the "w" clips that Yamaha went to on the later models. HTIKid already posted a link to one that will work fine.

If you want a brand new exactly like original with the brackets... you might find one eventually if you are prepared to spend a few hundred $$$

I guess ideally you'd want the early headlight with the replaceable bulb facility? I have one (see photos), but I don't know if I'm keeping or selling - I have replaced my blown bulb on the sealed beam unit with a H4 replacement (I'll try and find my tutorial), but I don't yet know how it performs.

This is on fleabay. A bit pricey, but you could try and beat them down and also sell on what you don't need - I reckon that it has the rare, original high beam warning light that might be worth a few £££/$$$.

1969 Yamaha CT1 175 Headlight Assembly w/Upper Covers Color Orange - Used | eBay

   


 

Looks my tutorial has been archived to free up space for photos.

Basically:-

Carefully bend back the five retaining tabs.
Start pulling out the bulb - note, it will need breaking to remove, and then you'll need to clear out all of the glass shards from the lens.
Buy a 6v H4 bulb.
Remove the collar from the H4 bulb (might need gently grinding off).
I think that a 1mm washer is needed, with the inner diameter of a smidge over the diameter of the H4 bulb and an outer diameter of that of the collar on the original, broken bulb - this is needed to seat it in the rubber damper. 
Fit the H4 bulb, taking care to align it properly.
Prise the tabs back down.

Make sure that you fit a 6v voltage regulator, or your bulb will just blow again, and the five tabs will only tolerate being bent a few times!

One note is that while modifying a used sealed beam by installing a new bulb will produce "light", it's not likely you'll have a headlight that is actually usable, safe, or legal, to ride with in the dark. The bulb filaments are precisely located by the factory at focal points of the reflector which is unlikely to happen when installing a different bulb into the old reflector.