Lance’s CB1300 Special

Every now and then along comes a mind-bending job, and here it is.

This super-cool CB1300 rolled up at the workshop after about 18 months of build. De-lugged frame, WSB-level front end, a swing arm fabricated by Kenny Roberts’s old MotoGP team in Banbury, a luscious exhaust, a new oil cooler and radiator, fabulous wheels, and so on.

Owner/builder Lance had taken a shine to a Stack dash. It’s actually a US-made race car system, so it has lots of long sensor cables attached which you can’t really shorten or remove. So you need to figure out how to hide all this excess. And the sensors cost a small fortune. But I have to agree the dash itself is very neat. It can do a bit of data logging and lap timing stuff, but here it’s going to be configured to display just mph, water temperature and revs.

The other electrical speciality was a Clearwater spotlight. Lance had hoped this was a main/dip setup but unfortunately it’s a straightforward spotlight, so for MOT purposes we cooked up the addition of a conventional LED headlight. Warning lights are handled by a little five-LED Motogadget display. The flasher unit is a titchy Joost one, because space was starting to look cramped.

The bike came with Honda’s stock ignition but with no wiring diagram available for the 1300 we eventually concluded it would be easier to install and run a new Ignitech ignition instead. And because there’s a lithium battery in the tail, we needed a MOSFET regulator rectifier. These are less violent in their voltage control than a traditional shunt reg rec, which just wallops excess voltage to earth. Lithiums are happier with gentle voltage control.

With all the above in mind, the first job was figuring out how to combine all this aftermarket stuff in the simplest way. Once I’d tucked away the cabling for the spotlight and Stack dash, it was easier to see where everything else should go. As I drone on about ad nauseam, the hard bit of building a loom is figuring out the routing around the bike. The actual electrical connections are easy by comparison.

While the bike was in the shop the last major item arrived – the carbs. These are trick Mikunis, and can run with a TPS (throttle position sensor). Lance is going to use the Ignitech pin ID to connect it up. The result should be better low speed power as the Ignition juggles spark timing at small throttle openings.

I really enjoyed wiring this bike up. Even if it’s a lot more complex than it looks.