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Posted By: kboyd LED replacement bulb in Lucas headlight - 06/04/19 3:36 pm
I used to be on here a LOT, back when I had my old T100 bitsa... It's gone, but now I'm sorting out a nice '69 Daytona and have wandered back. Had a brand new Lucas headlight assy with new bulb/connector/etc and I noticed the low beam had gone out at around 50 miles after the rebuild/restore. I just used the high beam for a bit, but now at about 90 miles the high beam went out too... so only the pilot now.

I saw a couple of other LED headlight threads using the search function, but did not see this type of bulb discussed. It's an ebay auction and you can choose different brightness levels, positive or negative ground, etc. Anyone around here try them?

Ebay LED Lamp

Thought I would ask before buying... Are they any good? Curious about how many lumens I need as well.

Thanks for any insight! So glad to see this site still up and running... Wish I still had my old black/silver t100, that thing ran so good and was so fun to ride.
Posted By: MarcB Re: LED replacement bulb in Lucas headlight - 06/04/19 3:43 pm
Here is a good blog post from one of our forum sponsor:
https://www.classicbritishspares.com/blogs/news/bpf-headlight-bulb-testing
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/04/19 4:55 pm
Originally Posted by MarcB
Here is a good blog post from one of our forum sponsor:
https://www.classicbritishspares.com/blogs/news/bpf-headlight-bulb-testing


Thanks... That's a good reference. Too bad they are out of stock of the one they carry.

I used to run a 5 3/4" sealed beam halogen on my old T100 and it pulled a lot of current. Too much for my old stator...
Probably not the answer your looking for but have you looked into what is killing the bulb off early?

Also If a standard RM21 alternator is struggling to keep up with a 55w headlight bulb then it might be worth checking the rotor for decent magnetism or failings of the wires from the stator or failing regulator.

As an alternative Wipac made a series of quadoptic headlights which take a H4 bulb, better lighting with their prism design and cheaper and more available bulb fitment.

More on the note your looking for there is a post about a complete LED headlight unit fitted into a 7” shell. I’ll post it on here if I find it.
litterally only 2 posts down from this one....

Mark Z’s headlight thread
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/04/19 7:15 pm
Originally Posted by Allan Gill
litterally only 2 posts down from this one....

Mark Z’s headlight thread


Thanks for the replies. I assume vibration? My old T100 was so much smoother... Maybe a carb sync? I don't know, I am new to this bike. Well, I have had it on and off for 15 years, as it was a family restoration project that got passed around. I was actually able to get it titled and road legalized, so it is I'm my garage for the moment and getting a real life shakedown. Working out the bugs now, I guess.

I read the "Mark Z" post and even another recent one from back in April or so. Just didn't see any reference to the type of bulbs in the auction I was looking at. I would like to keep the original Lucas headlight in there if possible. Those new ones look cool, but this bike is all original and I want to keep it looking stock (although that is not my usual style).
The trouble with sealed beam headlights is - they have really good light { have one on my trident] but what happens when you blow one??? Late at night on a bit of a trip?? Most service stations/roadhouses/gas stations carry bulbs and such, but I don't think I have ever seen any carry sealed beam headlights. A torch and racing tape would be the only option ohno

So I have gone back to a H4 headlight lens and am going to fit a CBS LED unit [its sitting on my bench saying 'Look at me, look at me' every time I go out to the shed smile
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/05/19 12:52 pm
I agree on the replaceable bulb... Especially with a new Lucas H4 lens and all. I went ahead and ordered the 12v positive ground 1800/1200 LED bulb assy. We'll see how it works out!
Posted By: MarcB Re: LED replacement bulb in Lucas headlight - 06/05/19 1:36 pm
Originally Posted by tridentt150v
Most service stations/roadhouses/gas stations carry bulbs and such, but I don't think I have ever seen any carry sealed beam headlights. A torch and racing tape would be the only option ohno

I've actually wondered about this before. I have modern LED flashlights that are brighter than some car headlights. Definitely brighter than what is mounted to most old bikes.
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/05/19 3:05 pm
Originally Posted by MarcB
Originally Posted by tridentt150v
Most service stations/roadhouses/gas stations carry bulbs and such, but I don't think I have ever seen any carry sealed beam headlights. A torch and racing tape would be the only option ohno

I've actually wondered about this before. I have modern LED flashlights that are brighter than some car headlights. Definitely brighter than what is mounted to most old bikes.


I had a coworker that was into bike riding (pedal type)... It was amazing the tiny lightweight super bright LED headlights those guys use.

https://www.outsidepursuits.com/best-bike-headlight-reviews/


Illinois is one state that only requires bikes to use (quote) "A white light visible for 500 feet." The words "headlight' or "headlamp" is NOT in the Illinois law because, when negotiations were underway for the law in 1968, many old bikes could not sustain having lights on all day because the old Harley generators couldn't feed the battery enough of a continual charge to keep the battery charged "up."

I know this because I was Secretary of the old Illinois State Motorcycle Association and sat on the advisory committee that determined how this law should be written.

IF your state only requires "a white light visible X number of feet," one of these bicycle lights might do the job.

Posted By: Mark Z Re: LED replacement bulb in Lucas headlight - 06/06/19 1:01 am
I ran a sealed beam incandescent automotive headlight for many years. I didn't find availability to be a problem, as places like AutoZone and Advance Auto carry them, but, lighting was not great, and power consumption was excessive. I also saw the price on these go from $7.99 to $17.99 over the years.

The main comparison in my other thread was between sealed beam LED headlamps and the LED bulb as supplied by outfits such as CBS. Advantages of the bulb are, a more natural-looking lens, less finagling with wiring, and I believe even less energy consumption than the sealed beam LED.

I stated that I went with the sealed beam LED solution because I do not have an OE lens, reflector, or connector. All said and done, I'm happy with it, except for the non-original, non-period-looking lens. And BTW, my battery is still staying fully charged (I've been checking it regularly). If the LEDs live up to their reputation for resiliency and longevity, replacement/availability shouldn't be a problem for a long while (hmm, I should have bought two of the suckers!).
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/06/19 8:27 pm
Originally Posted by Mark Z
I ran a sealed beam incandescent automotive headlight for many years. I didn't find availability to be a problem, as places like AutoZone and Advance Auto carry them, but, lighting was not great, and power consumption was excessive. I also saw the price on these go from $7.99 to $17.99 over the years.

The main comparison in my other thread was between sealed beam LED headlamps and the LED bulb as supplied by outfits such as CBS. Advantages of the bulb are, a more natural-looking lens, less finagling with wiring, and I believe even less energy consumption than the sealed beam LED.

I stated that I went with the sealed beam LED solution because I do not have an OE lens, reflector, or connector. All said and done, I'm happy with it, except for the non-original, non-period-looking lens. And BTW, my battery is still staying fully charged (I've been checking it regularly). If the LEDs live up to their reputation for resiliency and longevity, replacement/availability shouldn't be a problem for a long while (hmm, I should have bought two of the suckers!).


Excellent info... I'm anxious to get the new LED lamp assy. The old Lucas bulb worked ok, but I would like to see a bit better at night.

My old 500 had the 5 3/4" sealed halogen worked good, but was still a bit dim for highway speeds at night. Plus, it was a power hog like you mentioned. If I pulled up to a stop sign at night with the blinkers on the headlight would pulse dim/bright/dim/bright... lol. Still loved that little single carb 500... It would run 75mph for 2-3 hours on the interstate without a hitch! My current Daytona I hesitate to get more than 5 miles from my house.
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/27/19 2:28 pm
I ended up ordering the 12v positive ground 1800 lumen hi beam/1200 lumen low beam LED headlight. Finally received it and wow... what an improvement! Hopefully it will withstand the test of time and vibration that only an old Triumph twin can dish out.

Just following up and passing the info on, in case anyone else is thinking about a "drop in" LED replacement bulb.
The one on ebay that you linked to, that's the one you bought?
Posted By: kboyd Re: LED replacement bulb in Lucas headlight - 06/28/19 2:32 pm
Originally Posted by leon bee
The one on ebay that you linked to, that's the one you bought?


Yes sir... The link is in the first post in this thread. They have three different LED bulbs with different brightness levels, all available in 6v or 12v, negative or positive ground. The one I bought was a little pricey at $32.99 I think, but kind of worth it considering my brand new original type bulb lasted less than 100 miles before both high and low beam went out. It's a bright white light, like a "daylight" type of bulb, as opposed to the warmer "cool white" of the original. Took a couple of weeks before I received it, but it was rainy so I wouldn't have ridden much anyway.
Thanks, I think one of those would be pretty good in the parts stash.
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