You can buy an LED version of this light from Goffy, but it doesn’t bolt straight on. We chose to renovate the original

The integral lever perches on the bars meant the hi/lo switch had to go here. I sliced a bit of handlebar grip away to give the switch toggle room to move

Bracket to reposition the tool box also carries the ignition switch. Joe will paint the bracketry green later

Apart from the battery under the seat, everything is well hidden

Joe’s BSA Bantam D1 175

Joe’s owned this late 1950s Bantam for decades, and loves it to bits. Which goes some way towards explaining why he wanted such a massive upgrade.

The idea was to fit a 175cc motor (the standard one was 125cc), and max it out electrically. That meant an ElectrexWorld CDI/alternator, indicators, a 12 volt battery, a regulator rectifier, a horn, an ignition switch, a revived tail light and a new LED headlight.

Not one piece of this gubbins was fitted to the original bike. OK, it had a Wipac alternator which we swapped out for the modern one. But apart from that we needed to find a home for everything. Cue a couple of days making brackets, installing the engine, replacing knackered fasteners, making spacers and figuring out how it would all fit together.

Example: the bigger engine means the carb fouls the tool box, so that needs to move back further back, so you need to make custom brackets that preserve its upright position. As you are working in a space that a mouse would find cramped, it takes a while. Likewise fitting the flasher unit in the headlamp shell, on its rubber anti-vibe mount.

The bits you really can’t hide are the battery (the smallest gel battery I could find on Tayna), and the regulator rectifier. I decided they could only live under the seat on an aluminium plate. I didn’t want to start welding tabs on, so the plate had to sit on P clips. You need to make spacers for the clips to get a good enough grip, but not so tight the clips distort.

We decided on Lucas replica biscuit-tin switchgear: hi/lo and horn on the left; indicators on the right. The Goffy 5 3/4in headlamp conversion gave a clear, bright light, and the indicators (chosen by Joe) work nicely with the bike.

All in all, a ton of work for a tiny bike. But it should be the best Bantam in Norfolk when Joe gets it home.

Here’s the ElectrexWorld CDI and alternator. Not that easy to time up, but you get it done eventually

Wipac headlight switch was busted but impossible to replace, so it got fixed. Indicators fit into holes drilled in the headlamp nacelle

When you are adding so much hardware to a bike with no bodywork, all you can do is use bullet connectors and hide them under the tank

Looking cool. The tank and headlamp shell are hiding a lot of electrical action