Skip to main content
000798 000801 000804 000807 000810 000813 000816 000819 000822 000825 000828 000831 000834 000837 000840 000843 000846 000849 000852 000855 000858 000861 000864 000867 000870 000873 000876 000879 000882 000883
English French German Italian Spanish

Fitting LED lamp


Although I've read a lot about Halogen and LED lamps on this forum, I have a simple question.

Is there a LED bulb which I can easily fit into the standard old bulb holders on my 1961 ES2 and 1956 Dominator? I don't particularly want to change the reflector etc.

Forced to ride with the headlight permanently on creates problems.

Thank you


Yes. Try Paul Goff.  Also..don't forget the headlight holder probably won't be pre-focus, so take care to focus it with care.


I fitted LED's from Paul Goff to my final build Dommie racer. Not turned them on yet.

I could smell a rat when Hillary Benn banned the sale of old style bulbs for domestic use.

I have not yet found a link with auto's but there is a danger link with public lighting as a weapon and the interaction with 5G. Please do your own research and please don't come at me with self censored quotes of conspiracy theorist beforehand. (Wiki, Fact Check & Snopes etc is not research)

I intend at some point to change back to the old bulbs and have stopped using my LED reading lamp. My eyes appreciate the change. 

I find on my 16H (6V) that a Good reflector and pilot light is better than the yellow candle light 25/25 headlamp bulb.  Just a thought........

Ride safely.


I do not wish to enter discussions about conspiracy theories. So just a couple of technical observations.

The lights on our bikes (LED or otherwise) are run from a DC battery source.  Therefore they provide a steady light with no stroboscope effect. In that respect they are the same as conventional incandescent bulbs.

The power spectrum of incandescent lights is smooth.  That is to say there are no spikes at particular frequencies.  The compact fluorescent type used in low energy domestic lights in recent years have a very spiky spectrum, with high energies at a series of particular frequencies. This worries me because the human eye did not evolve to receive such signals. I suspect that the brain interprets this light as if it is averaged over the same range as daylight so it cannot control the iris or our natural reaction to avert our eyes from over-bright lights with the theoretical possibility that we might begin to lose our ability to see light at those spikes.  I've never seen this discussed but once again it is not relevant to our bikes.

Now for LED. These actually have a much smoother spectrum than fluorescent lights and are closer to incandescent (and thus to daylight).

Therefore there is no scientific reason to reject LED as hazardous for road vehicles on the basis of the type of light they produce.

The only other issue that worries me is one that all of us must have noticed but nobody talks about. It is the tiny sizes of high intensity headlights on oncoming vehicles. I cannot think of anything in nature that would prepare the human eye for seeing brilliant pinpoints of light surrounded by pitch blackness apart from the full moon in a clear sky. And a clear moon in a dark sky is painful to observe.  And we know not to look into modern brilliant LED torches.

Once again that is not relevant to us riding old motorbikes.

Finally on the subject of street lights. The attached picture is of a local LED street lamp at 1/10 second exposure taken when moving the camera. Since the mains frequency is 50Hz there should 5 frequency cycles visible if street lamps flicker.  That is either 5 (or 10?) pinpoints of light. Actually there is no sign of stroboscope effect, so street lights have no flicker (which is logical because it would be dangerous) and since they have a moderately smooth frequency distribution of their spectrum (like other LED) they cannot be any more harmful than other lights.



in answer to your initial question.  I have fitted an LED pre focus headlight bulb, which is a direct replacement for the old original bulb along with a stop and tail light bulb, again a direct replacement.  Both were supplied by Paul Goff, and I fitted them as I have Electronic/coil ignition which puts additional load on my 60 year old alternator and I do like to ride with my headlight on.. 

I can now ride with the headlight on without worrying if the battery voltage is going to drop to a critical level and cause problems when kicking the Dommi back into life. I have ridden a few times in the dark and I think that they are an improvement over the original bulbs. I certainly would not swap back to the old stuff.... 

Hope this helps. 



..... for your valuable and interesting posts.

i certainly will try Paul Goff. 

David, very interesting, you certainly are well up on these technologies. But how does one focus an old bulb holder?




I only know the ones I have. My prewar bike has an LED headlight with the bulb holder in a clamp like a hose clip to fix it to the reflector. So it can be moved back and fore. It's a fiddly job.  If yours has no such clamp then presumably there's no need...I don't know about the 50's design.  My Dommie (1963) has pre focus bulb but I'm not using an LED in it.

One little issue, and I don't know if anyone else has noticed this, but I've been using an LED in the speedo. I think a normal bulb might be better because the little bit of heat keeps the internals dry in bad weather.

David's comments point (pun intended) to a pet beef of mine — namely the absurd fad for tiny indicator light fittings.

Vehicle lights (should) convey information to the observer about both bearing and distance, and — very importantly — changes in these.

It ought to be well-known, but apparently is not, that point light sources convey no information about distance. (This is why the ancient Greeks considered the fixed stars to be literally fixed — in other words, attached to — a sphere enclosing the Earth.)

Thus they cannot convey any information about change of distance, and hence no information about rate of change.

Powerful headlamps are of course desirable for the purpose of finding one's way along an unlit road. But apart from this the obsession with high-output but tiny lights is not merely misplaced but actually harmful to road safety.

Avoiding other road users at night requires them to show lights with the largest possible lenses. The light output — subject to being powerful enough to be visible in poor weather — is far less important.


Well said Julian.

Thinking about it (Even more) I can only see a real advantage , and I was in that situation at one time, is with the loss of charge and running directly off the battery, An LED stop lamp for that occasion would have come in handy. (Save some battery for the Boyer)

Otherwise a case of change for change sake..Me thinks. (And I was taken in but since recovered)

>> David Cooper on Sun, 23/01/2022

"The lights on our bikes (LED or otherwise) are run from a DC battery source.  Therefore they provide a steady light with no stroboscope effect. In that respect they are the same as conventional incandescent bulbs."

My understanding, and I might be completely wrong, is that in order to get the maximum brighness, LEDs are over-driven, i.e. they pass a high current. But to prevent them "burning out" they incorporate a circuit to switch them on and off at a frequency that is not detected by the eye. So they do 'strobe'.

I wait to be corrected; we built bright lamps for bicycles from simple LEDs with separate driver circuits a few years ago, maybe they do something different now.


I believe that for maximum efficiency (as opposed to maximum brightness from.a given element) street light are run using DC.  As always it's not easy to separate fact from fiction!



LEDs are run with DC. SO street light power AC must be rectified to run the LED. Nothing to do with efficiency, just make it work. There is a serious efficiency improvement by the lack of heat. Ie incandescent lamps use power to get hot. Also as well as some LED being strobed to give us light, LEDs used in vehicles if/when they fail they can often flash at a low frequency making them very annoying. They are also very susceptible to the voltage supplied to them. I have in the past used cheap LED in the car called 12V but of course the Voltage in the the car is 14V. This is a 14% increase LEDs do not like this. Mostly these days decent LED for Vehicle usage will have a decent regulator built in. AND LED are polarity conscious BUT when they have a decent regulator built (for Automotive use) they can be made to be positive or negative earth. Answering Stan above, LED do have regulators to stop them being burnt out. But when they are designed they are regulated to NOT burn out, They are NOT over run. In fact they are run to give best light for an acceptable life ie NOT burning out. 


A drawback with LED is that they lose brightness with time. Incandescent bulbs do so to some extent but generally they fail entirely at the end of life. LED in the home (where they are used fur hugely longer numbers of hours per year than on most bikes) go dim and need to be changed after a few years. The discharge lamps I know of (in a local church hall) do lose some brightness but they also go out eventually. I wonder if local authorities will have (or be able to afford) regular brightness checks and LED replacement? Or will the lights lose brightness so slowly that it will not really be noticed?


The earlier LED replacements for BPF bulbs were hopelessly unfocussed, lighting up everything except the bit of road you needed to see. The current lensed offerings are good though. I got mine from Just what you need on a Velo with a 40W Miller dynamo. I still prefer incandescents on my 99 as, with an alternator, you are as well warming up your headlight as your rectifier heat sink with your redundant wiggly amps. Anyway, I have a box of BPFs still to use up so no rush to replace.


But try buying a 40, 60 or 100W bulb for your house. (Hillary Benn)

Not broken, so why fix it?

Actually, this only applies to domestic bulbs, so you can still buy 'proper' bulbs also. (For industrial use)

Auto bulbs are a tiny part of the market and have less future implications.

There are still safety issues with auto LED's as is well documented..

Why did I fit them on my last build? I must have been under 'Mass hypnosis' a term Eric Clapton recently used. Though maybe I was just a fashion victim?


At the risk of turning this into an electronics forum, I'd like to respond to Al Oz's post above...

We agree that LEDs are DC devices and there are several ways of powering them. Simplest is a passive resistor to limit the current at the applied voltage, Then there are constant current drivers that accomodate supply voltage variations (like Commandos at high/low revs) and variations in forward voltage as the LED heats up. Both these methods run the LED at a steady current and brightness. Finally there are pulsed LED drivers that rapidly switch the diode on/off. This seems to be the preferred way of driving LEDs now (and can also be used for a dimmer capability). More complicated, but fortunately available in an IC package Pulse drivers inevitably result in a strobe effect - which can be useful:

Putting more current thru an LED makes it brighter and, in order to get the same average light output as a steady current, the on pulses are at higher current than the LED can sustain long-term. In the past, we could get a simple LED to shine brighter by pulsing at high-current than the constant current route. Made some DIY bicycle lamps with a 555 timer - pitiful by today's standards :). This is what I referred to as 'over-driving'. Sample technical discussion: . I don't know whether automotive LED lights for use this method but bicycle lights appear to, so I would expect LED headlamps at least to go down this route. But perhaps not indicator / stop / tail lamps.

I think we're on the same page Al, but thought it would be useful to expand.


As we should know, DC can be used to execute people. The US electric chair for example. Try doing that with AC.

Anyway, keeping with the the original question.It comes down to politicians making the public do things that are not always in the public interest. For me, headlamps are for use in the dark.

What will they be mandating next? Ethanol in petrol or just excluding old bikes from the road? 

Electric scooter anyone?  Rushed through without much safety data.....


I bought an LED headlamp bulb for my Dominator, the 6V 'Daylighter' (the one with a domed lens on the front) from Paul Goff,  This is supposedly 10W.  When checked on a friend's power tester, it drew somewhere around 1A.  It is not really a huge amount brighter than the previous QI bulb. 

What I would really like is something that will properly illuminate the road, and it's absolutely fine to draw as much current as the standard bulb, 6A at 6V, etc.



The brightest ones need electric fan cooling. Someone might know if that's what limits what we can practically fit inside a closed headlamp shell.  The bulbs of domestic LED are cool, but the bases are hot.  Also mine certainly aren't lasting indefinitely.


If you are still using the original 6 volt ac switching system and then fit LED headlight bulbs, there is a possibility of boiling your battery. The original system was designed to run with a certain load so as not to over charge the battery. Best buy a proper electronic regulator/rectifier to control output.



When I switch my lights on, it barely registers on the ammeter.  The needle moves a small amount, because the LEDs have such a small current draw.  As I wrote last night, the headlamp is around 1 amp, and the other lights even lower.  That is not going to challenge the standard charging system.

What I want is a headlamp with power to light up the road so I can see where I am going at 60 or 70mph, which is still not the case.



Which is quite easy to do with a new rectifier/regulator and now run a Wipac Quadoptic Halogen reflector with a Philips Racing Vision halogen bulb.  The light up the road is fantastic and I can easily do up to illegal speeds at night with comfort.  The low beam pattern and cut off is also great with a generous flick up to the left.  I use an LED stop/tail bulb.

With my heated grips on max and headlamp on full beam, I can still maintain a slight positive charge to the battery, but I have to be doing 50+ to maintain this - if going slowly, I have to turn down the heated grips to compensate.

I use an LED headlamp on my 63 Ducati due to the measly alternator output of 55watts and have tried several different manufacturer's (and supplier's) bulbs - all of which are rubbish in my opinion and to get a good high beam, the low beam is usually miles off - but then, I'm not using a dedicated LED reflector, so the little Duke never goes out at night.

But the ac system switched out alternator coils when the lights weren't on so balancing the load. It will be a problem when the headlight is switched on and all the coils in the alternator are connected. Then the LED will not load the system as much as a standard filament bulb and risking boiling the battery.



There appears to be some consensus that LED stop tail lights (The ones we don't see while riding) are good while headlights remain a concern in some quarters.

As said before, if the charging system fails, one can still use the rear brake (Light) without taking too much out of the battery using LED.. (In my experience it was a failure of the Boyer Power box)

There may also be a case for a pilot LED to get you home in such circumstances.

But an LED headlight in an old motorcycle?

FWIW, my LED headlamp bulb on my M50 is fantastic when riding,, EXCEPT, that when idling, it very noticeably strobes in time with the tickover, much like the direct lighting on a villiers-engined invalid carriage, it does this even with a fully charged battery, none of the other lamps, pilot, tail, speedo, tacho, which are all LEDs do this.


Try adding a capacitor in the same way as the 2MC, this will smooth the ripples in the current flow. Or get a bulb with a better internal regulation circuit.

In reply to by paul_nicholls


used the lighting switch not just to turn  on  the lights, but also to switch in extra lighting coils in the alternator.  That raises issues with ALTERNATOR lighting systems.  Anyone with such an early Lucas alternator will be well advised to convert to a modern control unit, which can control the actual output.  It can also draw a much higher output than the standard original, which has no bridge rectifier.  Having a bridge rectifier immediately liberates lots of extra watts.  It's a seriously good idea.

Not everyone uses an alternator system.  There are actually lots of bikes with dynamos, including my Dominator.  The Lucas regulator operates its cutouts automatically, and really does not mind if the battery is fully charged and no circuits active, or is charging due to low battery voltage and headlights on.  It is limited to 60W or 48W depending on the dynamo fitted.  Important point. you can run a low-current or high current headlamp, as long as it does not overload the dynamo causing it to overheat.   It does not cause any problems whether you run a 1A headlamp or a 6A headlamp. 

My Paul Goff LED headlamp is 1A, 6W.  I want a much more powerful one....


Norton Owners Club Website by White-Hot Design

Privacy Policy