Introduction: Twin High-Power LED Motorcycle Headlights

Picture of Twin High-Power LED Motorcycle Headlights

This guide shows you one way to make a pair of high powered LED headlights for your chopper, hog, crotch-rocket, cruiser, scoot, or just plain motorcycle.  The design uses readily available copper fittings for the housing and some bronze threaded rod for the mounting.  Each motorcycle install may be different than that depicted here but the general idea is applicable.  Similar techniques are detailed in some of my other instructables linked below.

Step 1: Materials

The bill of materials for this build is :
1x: 12" of 5/16"-18 threaded bronze rod ($13.59)

2x: 1-1/4" standard copper coupling w/o dimple stop ($3.48)

4x: 1-1/4" standard copper cap ($2.19)

1x: 1-1/4" heavy duty Type K copper pipe 24" ($25.31)

2x: Neutral-white Cree XM-L star ($11.14 Cree Part# XMLAWT-00-0000-0000T50E4)

2x: Carclo 26.5 eliptical lens ($1.59)

2x: Carclo 26.5mm lens holder ($1.59)

1x: BuckBlock 2100mA driver ($19.99)

4x: Bronze 5/16"-18 machine nuts ($8.40 for 25)

1x: Cable gland with strain relief ($2.64)

Misc consumable items:
Lead-free solder for copper pipe (~$18.00 for 1 pound of solder)
From any hardware store

Conductive epoxy for mounting LEDs (~$35 for a 14g kit)

Regular epoxy for sealing, can use clear or filled (JB Weld e.g.)
From any hardware store

6 feet of 2 conductor stranded wire of at least 22 gauge

Silicone RTV for sealing lens to body
From any hardware store

Tools needed:
Drill bits (1/2" and 7/64")
Propane torch
Common sense: Build safely, saws can cut you and torches can burn you.

Step 2: Cut and Prep Parts

Picture of Cut and Prep Parts

The copper housings for these motorcycle headlights are going to be built nearly the same as the bicycle lights I detailed previously .  The difference is that the housing for the motorcycle lights will be made with 1-1/4" fittings rather than 3/4" fittings.  Also, the coupling is used full length to give the housing enough room to hold the BuckBlock and the pipe cap to hold the LED is cut taller and includes an internal section of 1-1/4" pipe to increase the thermal mass and make a better fit for the 26.5mm lens and holder. Also, the mounting style is different and uses a threaded rod rather than a bent wire cleat.

Holes for the wires to the LEDs also need to be drilled at 7/64" or so, holes for the threaded rods need to be drilled at 5/16" or so, holes for the wire between the headlights need to be drilled at 7/64" or so, and a hole in the end cap of the headlight that will house the BuckBlock needs to be drilled for cable gland at 1/2" or so.  See pictures for more clarification.

The threaded rod is bent to allow soldering to the inside of the housing and to give the lights the correct aim when installed on the bike.  You'll need to take some measurements of the bike and come up with the proper angle.  Depending on the bike, you may opt for a different mounting scheme altogether.  We considered using clamps around the fork tubes but eventually stuck with the stock headlight mounting holes.  Bending the threaded rod will require the use of a vise to hold the rod while you carefully bend to the appropriate angle.  Once bent, cut to length and dress any threads damaged during bending and cutting.  To help the bronze rod stick to the solder, grind the threads that will touch the housing flat to clean any patina and to increase surface area.  You will have to file out the hole in the copper housing to allow the threaded rod to sit properly as well.

Step 3: Solder It All Together

Picture of Solder It All Together

Prior to soldering, clean all the copper pieces with emery cloth (320 grit is good) to brighten them up, and then brush on a solder flux on areas that need to be soldered.  Assemble all the pieces and clamp them in a vise to hold while heating.  Position the housing so that the threaded rod is held in place by gravity and add an extra weight (such as a spare pipe cap) on the protruding threaded rod to help hold it in position.  You need to solder all the joints at once, which can be tricky.  If you are careful you can solder some of the joints first and then keep the assembly cool enough while adding other parts that you don't melt the existing joints.  However, it is easiest to just solder it all at the same time.  Fire up the torch (wear eye protection!) and heat the assembly until the solder melts on the housing and wicks into the fluxed joints.  Oh, sandals are a bad idea as well since with all the heat and solder being applied you are likely to have hot melted metal splashing around.

Step 4: Wire and Glue in LED and Lenses

Picture of Wire and Glue in LED and Lenses

Next you'll need to run wires between the headlight pods (remember we want the LEDs in series) and wire them appropriately.  Solder the wires to the LEDs prior to gluing them into the heat sink housings since with all that copper getting the solder to melt will be a real challenge.  For wiring in series, you'll want the LED+ wire from the BuckBlock going to the "+" pad on one of the LEDs, and then a wire from that LED's "-" pad going to the "+" pad on the second LED and then finally a wire going from the last LED's "-" pad to the LED- wire on the BuckBlock.  Since we're not using the DIM wires on the BuckBlock you can clip those and tape/glue over the wire so it can't short to the housing.   Use shrink wrap on all wire splices so that they can't short together or to the metal housing.

Prior to continuing, it is a good idea to fire up the LEDs before committing to gluing things down.  Hook up a 12V source to the BuckBlock, observing proper polarity.  Only light the LEDs for a few seconds as they can get hot and damaged quickly without a heat sink.

Once the LEDs are wired and tested (be sure to thread the wires through the various holes in the housings before soldering) mix up some electrically or thermally conductive epoxy and glue the LEDs into the housings.  I used the lens holders and a rubber band to apply consistent pressure and the keep the LEDs centered while the epoxy cured.  If you are using an elliptical or otherwise non-symmetric lens then you'll need to be careful how you clock the LED in the housing since the lens holder only holds the lens one way.  In the case of the elliptical lens, the lines on the front of the lens need to be perpendicular to the ground when mounted on the bike so I made sure that they were rotated correctly prior to the glue curing.

With the LEDs glued down, test for electrical connectivity from the LED pads to the housing.  When using and electrical epoxy it can be easy to get extra glue to flow up onto the wires or pads.  We don't want the housings to be part of the circuit so if any shorts have happened scrape the extra glue away until it is an open circuit.  Test the LEDs again to make sure everything is working.  You can run the LEDs longer now that they are properly heat sinked.

Next, glue the lens holder to the LED and seal the holes in the housing for the LED wires.  I used a clear epoxy that I spread around the interior of the front end cap to seal the holes and provide glue for the legs of the lens holder.  Be sure that you don't get glue on the dome of the LED and in fact keep the glue away from the LED as much as possible.  Again use a rubber band or similar to hold the lenses in place while the epoxy cures.  Once the epoxy is cured (best to wait overnight) you can snap in the lenses.

Step 5: Finishing Touches

Picture of Finishing Touches

Once the lens holders and lenses are installed, you can seal around the lenses using any RTV silicone or similar.  I used a black liquid gasket RTV from an auto parts store that I had laying around.  That finishes up the business up front, now for the party in the rear.

The final touches needed to seal up the light are to fit the BuckBlock into the appropriate housing (the left one in my case), epoxy the inter-housing wires, install the cable gland, install the external power wiring, and then glue on the end caps.

I applied a big dollop of epoxy inside each housing at the strain relief knot to hold the knot in place and to prevent leaks.  The hole you drilled from the wires between the housings is hopefully really snug and on the bottom of the housing so leaks should be unlikely.

The cable gland includes an integral o-ring for sealing to the pipe cap but adding a squirt of RTV when installing is extra insurance.

Fitting the BuckBlock should be easy if you arranged things along the way and keep extra wire to a minimum.  Using shrink wrap or electrical tape on your wire splices is also a must.

Pack all the wires into the housings and do one last operational test to make sure there are no troubles prior to sealing up the housing for good.

Lastly, apply epoxy to the end caps and slide them onto the housings.  This will permanently seal the housing.  If you prefer you can try using a plumbers putty or non-hardening PTFE paste that is viscous enough to keep the caps on but will not permanently bond the caps on.  That way you can open things up in case something breaks down the way.  Another option would be to melt wax/paraffin to keep the cap on, since these lights will not get hot enough to melt the wax when in use.  Summer sun in AZ is another story.

Step 6: Testing

Picture of Testing

If you have access, testing of light output can be performed in an integrating sphere.  I happen to have built an integrating sphere a while back and it provides a nice and repeatable method for evaluating light output.  I don't have a calibrated source, but have been using a standard 120V 50W halogen MR16 bulb as the standard source.  The MR16 puts out 8100 Lux on my meter while the motorcycle headlights detailed above put out 12100 Lux each.  Based on published numbers for halogen bulb efficiency this is approximately 700 lumens from each of the motorcycle headlights.  Not bad, not bad at all.

Step 7: Mounting on Motorcycle

Picture of Mounting on Motorcycle

Finally, go ahead and mount the light on your ride.  You can paint the copper to match if you like or just let the copper age.  Do some road testing to see if the lights are aimed to your satisfaction, you want to be able to see far enough up the road without putting too much light in the eyes of oncoming drivers.  The elliptical lenses used in these lights has a narrow throw vertically but wide horizontally.  If the lights need to be adjusted you can carefully bend the threaded rod (difficult) or shim with washers or similar (easier).

Step 8: Beam Shots

Picture of Beam Shots

Finally had some time to take beam shots.  I did not have a tripod handy so the crispness is a little lacking but the results come across.  For comparison I also took some pics of the headlight beam from a stock CB550 with incandescent bulb on HIGH beams.  The photos show that the LED has a much broader beam and a lot more light in general.  The throw is pretty similar between the two with the incandescent is much more focused and directed.  From a rider point of view, the LED is a big improvement over the anemic stock light.  Comparison photos are taken with the same camera settings.


AkshatR (author)2014-12-04

Well done, and thanks for taking the time out to make the guide. Cheers!

tamasic1 (author)2014-08-17

Great build! I noticed in the step 8 pics you have a Honda SuperCub. Have you tried something similar for it using the stock headlight housing? There are a lot of scooter owners with a early 6 volt system looking for a low watt lighting setup.

jmengel (author)tamasic12014-08-25

Good eye. That isn't my SuperCub, but it does have an LED light that I build for it. The driver is a boost type, driving a 3-up XPG star but another good method would be a buck type driving a single XML. The stock headlight housing is terrible for LEDs from an optics and a thermal perspective but the owner didn't want to lose the "original" look. I could detail that build if you'd like. I've also done retrofits into several Honda city bikes (and two more waiting) from the 80s as well and should write those up too.

tamasic1 (author)jmengel2014-08-28

I can understand the difficulty of the issue. Like the owner of the Cub, I'd like to keep the original look. CPU's in a laptop only have a plate atop them with a thick copper strip that routes the heat to an exchange grid to vent externally. I wonder if the same would work with a LED headlight setup. Plenty of room behind the forks for a heat sink.

Yes, would like to know more about your builds. Thanks!

jmengel (author)tamasic12014-08-29

Yes, a "heat pipe" if you will can channel the heat to a remote sink, with some commensurate increase in LED temperature due to increased thermal system resistance. Can also use the frame itself as the heat sink if there is enough metal around.

GregT1 made it! (author)2014-08-01

Rad project. plenty bright + looks mean. I doubled the recipe

crazypj (author)2014-06-09

got a couple of the lenses for the 100w LED, they don't concentrate the
light enough, plus, as you mention, there is no cut off.. I was hoping
it would be closer to a projector light as used on modern cars.

play with lens position, move it forwards and back until I get beam I
want. Going to step up to 2-1/2" copper pipe which is big enough to
mount a 12 v fan inside, radial holes for airflow and make heatpipes
from 1/4" copper tube. The weirder looking the better for a steampunk

'Frenching' the lens inside pipe should cut down unwanted beam?

jmengel (author)crazypj2014-06-10

Curious to see a pic of the lenses you got for the 100W LED. Frenching, or recessing the lens and LED will change the spill of the LED, but you may need something like black-out headlight covers from WWII.

crazypj (author)2014-05-08

Thanks for Instructable, I can make stuff and adapt idea's but not so good at coming up with stuff :)

I like the idea of copper pipe, going to use it on my 'steampunk' XS650 but will use 32~36v-100w LED and a step up transformer plus 2-1/4" pipe (LED is little over 2-1/8")

Copper has much better heat transfer so can act as the heatsink but I may add a couple of 12v computer fans as well.

jmengel (author)crazypj2014-05-09

100W LED? Hmmm. Get ready to be ticketed. Good luck!

crazypj (author)jmengel2014-06-02

I put a light together to test, the beam patter is completely wrong. If I can find some way to control the light direction I'm going to make it Going to need some sort of 'standard' lens over the LED 'bulb' which will cut down efficiency somewhat :)

jmengel (author)crazypj2014-06-02

You aren't using a lens at all right now I imagine. Certainly not the lens I specified. The lens I specified cuts down somewhat on the glare to oncoming traffic by concentrating the light but still lacks the "cut off" of a true DOT approved headlight. Without a lens you are basically spreading all 100W of LED illumination everywhere with likely a half intensity angle of 120 degrees. Which makes for a blinding but ineffective headlight. You can try and fit a standard motorcycle housing over the LED but it will impact your cooling negatively (and thus LED lifetime) and the differences in source light from the halogen bulb and the planar LED COB (chip on board) array will make the housing lens (sort of Fresnel-esque) essentially useless.

Also, I don't think your 2-1/4" pipe is up to the task of cooling a 100W LED unless it is also about 48" long. So I'd be careful about running the LED while standing still. Will work better at 100mph or with fans as you mention. Still I'd expect your die junction temperatures are quite high and will lead to rapid failure.

Getting a lens for a large COB LED array is going to be difficult. You will not find anything off the shelf unless this COB is used on a production automobile. Designing you own is a difficult, solitary but satisfying option. Good luck.

slicknick3227 (author)2013-12-13

I'm in the same project except I'm putting my LEDs into a street fighter style headlight assembly this gave me a good idea were to by nicer more powerful LEDs instead of radio shack plus I will wire two seperate circuits now just in case on goes always keep the wheel turning I like your style of rat bobbers! It's awesome to see outside the box. And not mainstream style

MasterErik (author)2013-11-04

142$? Guess if you have some of the equipment. Good for a steampunk bike!

fourechodog (author)2013-03-11

Cool. Very nice. WAY over my head though!

ctaylor29 (author)2012-04-04

Quick Question,
Does the Buck Puck work as a resistor or do you need put one on the leads?
(I'm trying to do this myself right now and I dont want to fry my LED)
:) Thanks!!!

jmengel (author)ctaylor292012-04-04

The buck block is a constant current driver. If you wire the LED and power to the buck block as indicated in the datasheet you will be fine and will not need an additional resistor.

John Culbertson (author)2011-10-29

Love this on so may levels.

Quick question, how was the fit on the optics with the XM-L Stars? I have been looking around forever to find good optics and holders for them that are in stock.

jmengel (author)John Culbertson2011-10-29

The optics holder fits fine and is designed to fit any star board. The optics are designed to work with any LED, as long as the correct holder height (focus) is used. The optics holder available at is not designed for the XML LED. The stand-off legs on the holder, effectively focal length, is varied for the various LED designs. In looking at the Carclo datasheets though, the holder for sale at is only off from the recommended XML leg length by 0.1mm or so which I thought was close enough. In practice it looks to be close enough as the lenses perform well on the XMLs.

The lens and holder fit to the copper housing could be tighter though, but barring custom machining something it was as close a fit as I could get. Once more optics options are out there for the XML more housing possibilities will emerge.

dlemke (author)2011-09-18

Need to have a way to change lights in case of a burn out or malfunction. It is a real leg wettin experience to have both high and low beam burn out at 80 mph on a curve at night. I didn't see any back-up circuit for this option, since it is wired in series. Trust me, if it is on a motorcycle, it will need repair. They are very hard on lights and everything should be made to be servicable. On the bright side, this is an awesome idea and I'm sure many people will take advantage of it on custom bikes. You may even want to write in to that show, "Biker Build Off", if it is still running. They would need to modify them, and have a way to service them, as would anyone using this setup. You could also reduce the cost greatly by using a regular outlet for the copper supplies, as they are available at any home improvement store and McMaster Carr is expensive.

I also think you could use these as driving lights in addition to a regular headlight, like on a Harley Dresser, which has small driving lights on the side of the big headlight, and that would keep it legal in most states. Switching would be an option of the owner, but using a auto sensing switch from a Caddy would be a cool addition to your idea. That would auto dim the lights when someone came your way, although a lot of people didn't like them, as they would auto-switch when getting false readings from billboards, etc, but a key item, would be a proper digital delay to keep them from switching too quickly. Now you got me fired up, and I can see a whole lot of good things that can be done with this type set-up.

Thanks for the cool idea.


jmengel (author)dlemke2011-09-27

Also, I find that is the same price or lower for most of the copper parts. That and you can buy various grades of copper (thin or thick wall) as well as the 1 1/4" inch pipe in smaller 24" sections. Home Depot only sells it in 8' lengths ($$$) which is more than I want or need.

For example, the 1 1/4" coupler is only available with a stop at HD and sells for around $6. A 1 1/4" coupler without stop is only $3.50 at McMaster. Your mileage may vary.

jmengel (author)dlemke2011-09-19

Redundancy is a good idea. The original single bulb headlight did not have any however and my opinion is that the pictured LEDs and driver circuit will outlast the bike. You could use a driver in each pod and be effectively wired in parallel to the 12V headlight wire. Since the cost of the driver was a big part of the overall project cost, and the efficiency of the driver drops from 90% to 80% when running 1 rather than 2 LEDs in series we decided to put the pods in series on a single driver. Time will tell.

ZoDo (author)2011-09-26

Heh made it look like Wall-e :P

wdsparrow (author)2011-09-18

I think I'm pretty ignorant here. Someone please help. I have never understood why someone would use a LED driver circuit? Doesn't a driver circuit push the consumed power above LED rated power by pulsing it? You would never want pulsed headlights on a motorcycle because it's hard on the eyes. And running above rating will shorten the life of the LED which means failure on the road. Why not just use 12 volt DC current through a larger number of LED's and a resister? It's a cool instructable regardless of my confusion.

Monsterguy (author)wdsparrow2011-09-18

The reason you would want to use a driver with a high power LED is that they supply a fixed current supply to the LED.

Generally the only time a driver would be pulsing would be if you were dimming the LED via PWM, as long as the frequency is high enough the flickering is not readily visible.

The problem with using just a resistor is that the current the LED draws is then directly tied to the voltage. The current increase/decrease can be quite extreme with just a small change to the voltage, I assume that the power supplied by the battery on a bike isn't that smooth (as it's being charged)...but that's just a guess.

wdsparrow (author)Monsterguy2011-09-24


maxstevenson (author)2011-09-12

Nice Instructable! Can you post a picture of the whole bike? I'm sure many people would like to see it. Your pictures are great!

jmengel (author)maxstevenson2011-09-13

Thanks for the feedback. We'll see what I can do on the pics. I am also working on a set of side-by-side beamshots comparing the bike headlights to a typical car headlights. Stay tuned.

jmengel (author)jmengel2011-09-23

See step 8.

k0k0s79 (author)2011-09-18

Can you please add a night shot of these on the road to show their efficiency?

Dstrcto (author)k0k0s792011-09-18

I second this, please do

jmengel (author)Dstrcto2011-09-23

See step 8.

cway56 (author)2011-09-19

Harley has a set of them.. Cha Ching.

marcintosh (author)2011-09-19

I'll just leave this here -

LInks to a commercially available headlamp modulator. I had one years ago (1982?) on a CB650. I was never run off the road in city or rural driving.

I found this interesting as well

(has a link to above too). Poster lists legal and official federal guidelines for headlight modulation. I would double check, just because that's the kinda guy I am.
BTW- 'ible looks great.  Might just be the start of a steampunked bike.

owenbrau (author)2011-09-19

It's good to see the DOT catching up with technology finally. Can't wait for stock replacement for universal applications.

hirenpanchal47 (author)2011-09-19

Nice Idea Dear ,,
Now i am thinking to purchase New BIKE :)
to do this types Experiments ;)

I am in the shed! (author)2011-09-18

What about the beam pattern? or are these designed as spotlights?

These use an elliptical lens. 44x8 FWHM.

Bilby (author)2011-09-18

Nice instructable!

Looks like... hmm. At a guess, '75 CB450? This would be an awesome headlight cluster for my '73 CB350 cafe if I ever get it together.

As a proponent of never-enough-illumintion when it comes to riding, I can see a double-stack of these on each side, two with the slit lens arranged one higher then the other, and two pin spots. Low beam could have the lower-aimed slit lens illuminated, while high beam could have the other three illuminated as well. Not only would visibility be much higher but it would look even more hard core :D

jmengel (author)Bilby2011-09-19

Close, it is a CB550. Thanks for reading.

baratacus (author)2011-09-18

That's an amazing amount of light. I can't wait for your photos of the beam comparison to a standard headlight! With the sphere, does it matter whether or not you have the beam focused on the sensor? Or is the reading taken from just the bare LED and no focusing device?

jmengel (author)baratacus2011-09-19

The intent of an integrating sphere is that the sensor does not image any of the light output from the lamp directly. Thus, the sensor is off axis and an internal baffle/shade used to ensure all light imaged by the sensor is reflected off of the internal walls.

owenbrau (author)2011-09-18

Just so you know, LEDs are not DOT approved for headlights, so this would not be a road-legal mod.

kscience (author)owenbrau2011-09-18

Maybe not everywhere: Metro Transit in Seattle is starting to run LED headlights on some buses here. They have been traffic lights for years.

Using schedule 40 copper would be better for the high power leds you can get now; heat is totally their enemy. I would use thicker stuff so it could be threaded as well, I do not want to rely on thermal epoxy.

For a bit more surface area [heat sinks are rated by this, not just mass] I would solder up some fins radiating out around the housing, so air flow past will radically help remove the heat.

Lenses and or reflectors may be good too; 10 watt led's cannot be looked at directly without being blinded. DOT approved or not if a cop is blinded driving by you he's gonna nail you for it. Still- its absolutely time we start using LED's and getting over the learning curves. My porch light is 49 1/3 watt [they call em half watt but 3v @ 100ma ain't a half watt] straw hat led's in series on a 2oz copper dual sided board; 16 watts, it fluoresces the neighbor's license plates 2 houses up as it makes it easy to see the deck out front. its 16 watts max.

jmengel (author)kscience2011-09-19

The 2010 Toyota Prius (among other cars) is available with LED headlamps. The lenses shown in my Instructable are not DOT approved however.

The shown lights exhibit very little output droop with time (heating) in still air indicating adequate heatsinking. Past lights built for bicycle use with 3 LEDs in a star show significant (~10-15%) output droop when in still air.

rch (author)owenbrau2011-09-18

Actually, LED's are approved for headlights now. Harley Davidson sells an LED headlight now.
However, I doubt if there is any way on earth that this instructables' headlights would ever be considered DOT approved.

rwon (author)2011-09-18

These look great. Is it possible to get a properly legal high and low beam? Even if that isn't possible, they'd make terrific driving lights.

jmengel (author)rwon2011-09-19

Right now the limitation is lack of availability of optics for proper projection and cut-off.

fastm3driver (author)2011-09-19

FYI, Harley has real LED headlamps and auxiliary lights.

jmengel (author)fastm3driver2011-09-19

Thanks for the heads up. Pretty pricey, although DOT approved.

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