Chris’s Kawasaki Z650 B2

Chris has owned this Z650 for more than 20 years but with one thing and another he’d only recently started riding it again.

He did the usual recommissioning job on the carbs and motor, but the electrics were playing up: a very low charging voltage (around 12.7V), various lights not working, and poor ignition performance. Sometimes the plugs would soot up.

He rode it up from London anyway, and we had a long chat about the best way ahead. He didn’t particularly want a new loom, just a bike that worked reliably.

Once I’d opened the patient up, the poor charging and ignition issues revealed themselves. One stator cable was almost cut, and the non standard Lucas ignition had been repaired long ago – presumably not very well.

The loom itself was starting to burn, so it had to go. But I noticed Z Power listed a Z650B1 loom for just £350. That would be a lot cheaper than a scratch-built one. Could it be adapted?

The B1 had three-phase charging and no hazard flashers. Otherwise it was the same as the B2. I suggested the new loom was going to be the cheapest option, and Chris agreed. I then destroyed any cost savings by also recommending a new Dyna S ignition from Z Power (he already had the Dyna coils).

Adapting a B1 loom to a B2 bike which has Z900 switchgear and a different ignition sounds daunting. The solution is to go somewhere very quiet, and crawl through both wiring diagrams until you understand how they differ. Then you map the non-standard bits (switchgear, reg rec and ignition) and see how to use the new loom to do what you need.

Eventually you figure it out. The last job is to test/repair the peripheral electrics on the bike to make sure they work.

It helps if you know the Z900 switches. The horn button on the left cluster earths through the handlebars, and sooner or later it doesn’t work. I always add an earth cable from the switch, to eliminate the annoyance.

I also make up high capacity battery cables to every electric start bike I work on. On the B2, that means partially removing the starter motor, just to get to its terminal. Kawasaki eventually made it easier on later models.

Fitting a loom sounds like a plug-and-play procedure, but it rarely is. You usually discover different connectors, so it helps to know how to use a crimp tool, and to have a stock of common items – in the Z650’s case, Japanese bullets and 2.8mm Miniblock connectors. That way you can adapt the new loom, or the old bits, to connect up correctly. This becomes even more important when the loom is for a different bike.

It all felt easy until I had to skip work for a couple of days, about half way through the job. Getting all the simultaneous factors back into my head after I’d forgotten them all was a bit of an effort. But the bike fired up absolutely instantly, charged at 14.5V, and all the lights worked first time. Result!

Chris was really pleased. The bike went on to my friend Rupe Farnsworth (07950 234497) at La Contenta Motorcycles for some carb cleaning and balancing. It will be thoroughly sorted by the time Chris gets it back.