Marcus’s BSA A50 Royal Star
We’re on a bit of a run of Brit bikes at the moment. This lovely old thing had begin to fry its loom and was generally not doing much in the electrical department.
Marcus declined my tempting offer of adding indicators. He just wanted it to work.
As with every old British bike, building the loom was the easy bit. The real work was the two days before, which involved solving all the usual electrical issues that bedevil a 60 year-old motorcycle. To take a few examples: replacing the vibration-raddled headlamp shell, fitting an ammeter and warning lights in said shell, mounting the battery securely, replacing the antique coils with 6V versions for the Pazon ignition, fitting and timing the ignition, rebuilding the tail light, mounting the reg rec, mounting the new ignition switch, rewiring the handlebar switch, and plenty more.
It might sound massively tedious, but I love messing about with old BSAs. And anyway, if you don’t make sure everything works perfectly then a new loom won’t help much.
Most of the new goodies came from the obvious place: Goffy Electrical. The Pazon ignition deserves special praise. You stick it where the points used to be, and time it statically using the points mark on the alternator rotor. Then you wheel it outside to fine-tune the timing with a strobe. In fact the bike fired up first kick, and the timing was spot on already. Not often that happens.
We came across two issues: first, Marcus had bought a new LED headlamp bulb, but it would only provide main and dip together for some reason. I suspect the location hole in the bulb collar isn’t accurate enough. Second, charging was a measly 13.2 volts with the lights off. That’s a classic case of a demagnetised rotor. The cure is to fish off the primary cover, fetch the rotor off and replace it with a new one. Marcus has it lined up as his next job.