DIY led lighting.

I was asked in a headlight thread to do a DIY on LED lighting so I will pass on what I have done to add led lighting to my minibikes. I will cover the following, Advantages, Converting a period correct sealed beam to LED bulb, Led lighting for headlamps with replaceable bulbs, different types that I have used, using batteries, and comverting lighting coils from straight AC to DC, and using a smoothing capacitor and the reasons why. This is just my experience with comverting 5 Mini's to led lighting some battery, two techumseh with the minibike lighting magneto and a clone with the twin lighting coils.

1)Low Power
a) allows the light to be bright even at idle (not full brightness but close) when using lighting coil on a tec
b) much longer life when using a battery.

2) if you are doing a restoration and the headlamp is hard or impossible to find you can convert it to led and still have the original factory look.

Converting a sealed beam to LED.
I have converted a few sealed beams to LED using the following procedure and if you are going to do this make sure to wear safety glasses and gloves because of the danger of breaking the glass. I use welding gloves. I purchased a 1" diamond glass drill at home depot.

I first find the little tube that is on the back by the power prongs and break it with needle nose pliers to release the vacuum. Next I break off the metal power prongs. Then I clamped it down to the mill table and applying slight pressure start drilling while spraying with a spray bottle of water and it slowly cuts a nice round hole. You can do this on a drill press either clamping it down or with a helper holding the bulb. I put some thing rubber padding underneath the bulb so it wasn't resting on the metal table. If you have a helper you could do this with a battery drill and a friend holding the bulb, just remember light pressure especially when starting so it does not wander around. I used a bulb smaller than the hole for the sealed beam so I made a derlin adapter to hold it but now there are bulbs with a larger base you could just silicone in. The following picture is the one I did with the adapter and the next photo a bulb that you could just silicone in over the hole.

Now you have a old sealedbeam with a led low power bulb.

3) Headlamp with replaceable bulb.
This headlamp (I had purchased a few) I think was bought on OMB a while back but I have not seen them for a while, they have a modern bulb which can be found cheaply on ebay with leds. Here is a picture of the headlight and two different ebay led bulbs (both a couple of bucks shipped free from china) that fit it.

4) different types of LED bulbs both for replaceable headlight bulbs and the 1157 style led taillight bulbs with running and stop function.

5) Using batteries. My first use of led's I use Li-ion batteries from discarded laptops, then Gel cells but now I have found a nice rechargeable battery with a power switch on it from ebay for around 22 bucks with charger on ebay that I have found to work the best for me. My bikes sit for a long time between use and these seem to not lose the charge over time. I also found the connectors on the light side off ebay as well.

6) using the Tecumseh 3 amp lighting coil to power led lights. Here is a standard wiring diagram for the tec lighting coil

Now The way the coils are internally wired they take one end of each coil and tie them together and ground them, the other ends of the coils go to the red and black wires. Now Havesau Dave once had a thread on here about trying to use a full wave rectifier in these and it caused issues because the two coils are out of phase with each other and the floating ground. My implementation is copied from a older Tecumseh battery charging system.

So basically each alternator wire (black and red) each go to a diode with both diodes banded end away from the alternator output. Next I have a fuse (I used 3 A) and then a electrolytic capicator rated at 35 volts and 2000MFD. This was all available at the local radio shack which has unfortunately closed so now you may have to use mouser electric for the diodes and caps or a local electronics store like Frys. The capacitor goes negative end to chassis ground and positive end to the output of the fuse. This capacitor takes the positive electric pulses from the diodes and stores them just like a lead acid battery just much smaller capacity. This provides smooth steady DC power to keep the led's happy.

7) same as above but for a GX200 clone with lighting coil.
The Honda does not have the issues the Tec does. It does not have either end of the coil(s) grounded so in this case as well as any other engine with both ac leads coming out you can use a full wave rectifier, where the two wires go to the legs marked ac then the other two legs are labeled - and +, Plus goes to power the lights and negative goes to frame ground. In the picture I am posting here I run the output from the full wave rectifier (the square looking thing with 4 prongs, into a radio shack small project box with a fuse and capacitor, to smooth the DC. Then off to power the lights.
my little audio company stocks and uses tens of thousands of 1N4007 diodes on an annual
basis. they can be used as singles or four can be fashioned into a bridge. OLE did a
fantastic job of solving this application. i would be happy to send out diodes to anyone
who PM's me. i might even have the capacitors, i will check tomorrow and update.

cool stuff! :thumbsup:



Well-Known Member
good info ole4.....:thumbsup:
on my briggs build bike i got lucky. lighted coil was setup from factory with dc coming out.
something that i found out that work good for my project was my headlight case i use. it originally was for a emergency exit sign. cases are the 4inch. same as some vintage minibikes had...for example arctic cat,gilson,speaker...etc.
just converted the original light bulb to a led bulb.
they look just like a standard 4 inch light.

led lights work great for my project. gave me just enough amp's still to trickle charge the battery for my electric start..:thumbsup:

i believe this is the square 4 prong part you where talking about or something very close to it.
What is your system? Is it a tecumseh lighting coil or a clone with one or two coils? They all make ac output and it is unregulated so the tec with half wave rectifiers make about 18 no load and the two coil clones with full wave rectifier mid twenty. Depends on your load wattage and type if there will be enough to charge a battery. If you use led bulbs then even the half wave tec would keep battery charged.