Monday, September 30, 2019

Bantam goes LED - pre focus LED headlight bulbs

As I've been doing rather a lot of tinkering wiith my D1 Bantam of late and, frankly somewhat against expectations, actually enjoying riding it I decided to see what I could do to improve the lighting.

The bike now has an Electrexworld CDI ignition set but the output isn't massive so there is not a lot you can do above and beyond putting in a low-ish wattage halogen BPF headlight to improve illumination if sticking with conventional bulbs.

I was also very interested in sorting out the tail lighting as early Bantams have a horrible habit of regularly blowing the feeble torch type E10 bulbs used for the brake lights.

On my Bantam, despite the CDI set up, I stuck with positive earth and 6v. It would be very easy to go 12 but at the time I wired it I only had spare 6v bulbs and quite honestly, all things being equal, with a healthily wired system the 6 volts should be more than adequate.
Lighting as Mr Wipac never imagined it could be.
So tail first: as you probably know the Bantam Wipac rear light has a pair of stop bulbs and a separate tail bulb. The stop bulbs are E10 size. These are readily available in LED, just tap 6v E10 LED in to eBay and hundreds of options will pop up. Important for the Bantam is that you get bulbs with a very low profile. Multiple radial LEDs may seem like a good idea but they will not fit in to the space available so go for a single LED with a shallow dome. There are bulbs available in dual polarity, it's easiest to go for these. They are also available in red - this is a lot nicer, the blue-ish tinge to a white LED tends to overpower elderly plastics and makes the tail light unacceptably white coloured.

The tail light bulb is a BA15. Same applies as above, there's not a lot of space so go for a low profiled and not to bulbous bulb, in red preferably and with a radial spread of light. If the bulb is sitting right next to the plastic lense the effect is not nice.

Good news on the brake and tail lights is that they are very widely available and cheap as chips.
Wonders of modern technology. BPF LED.
The British Pre Focus P36D is slightly more pricey at typically around the GBP20 mark. There are a couple of different types available but the one I went for is as above. In operation it is pretty simple - there are two diodes, one faces up and one down. The down one is low beam and the two together constitute high beam. These bulbs cover voltages from 6 to 24v  and with this type you have to choose polarity. Other types are available that will do both positive and negative earth.

In use the headlight is definitely bright, way brighter than a standard bulb, not quite as good as a quartz halogen but it has about a fifth of the draw so therein lies your advantage for an elderly motorcycle. Plus LEDs are more robust and a more efficient use of power so what's really not to like. Standing still trying out the high beam it really does seem to illuminate way too much of the sky but once underway you find the it covers the road ahead too, I personally just find it slightly distracting to be riding along a country road and see that the tree tops ahead are lit up. It's probably a bit annoying for folks in rural residential areas too but the solution there is to go on to dip in built up areas.

To be a completist with the LED set up there's the pilot bulb to consider too. In all honesty you might as well ride with the headlight on all the time if you have LED and want daytime lights but the pilot is easy and cheap to replace too should you feel like it. Same as the brake lights, an E10 (also sometimes known as a minature edison screw - mes) although obviously in white not red. Once again dual polarity bulbs are available and easiest.

Overall a decent improvement. I use my old bikes at night on a fairly regular basis. I've been aware of a few nasty accidents of late involving slow and elderly vehicles being rammed by innatentive drivers of modern cars so anything I can do to avoid this is evidently a big bonus. Oh, and being able to see where I am actually going helps too.
Bright enough for you?


  1. I've thought critically of the little hood (like the bill on a cap) over the headlight that many seeking a vintage look will attach to their motorcycles these days. But I recently noted in an old photo that these apparently have been features of motorcycle lighting since carbide gas lights. Would you consider using a little hood to cut down the (I agree) distracting effect of lighting up the tree tops?

    1. Hi David, that's a good idea. You are right - from the early days peaks were a feature on acetylene lights. They were popular over here as accessories for both cars and bikes in the fifties and sixties. I'll just have to look around to try and score a suitable aged peak in the right size for the Bantam now.