Neural Connections

Hoping that this was a real break in the mystery, I took the bike out for another ride. Once again, it started off great but in short order the bike cut off again and I had to pull to the side of the road. Now I'm confident that my solder connections were very good so at least I prevented a future stranding incident where the bike would not start up. But I did not fix the problem I was chasing. It wasn't the ignition switch.

Something seemed amiss in the ignition circuit. Now that I knew I had reliable power thru the ignition switch I had to keep working my way thru the firing circuit.  I had replaced the hall sensor and built a test circuit to confirm that the sensors were working. I had aligned the sensor properly when I installed it, and tested the timing with my homemade ignition testing unit. Seemed like the problem might be downstream in the Electronic Ignition Unit. And that could get expensive.

So I returned to the basics.  I had cleaned all the contacts with contact cleaner from one end of the bike to the other when I first bought the bike. I decided to check the electronic brain of the bike and work my way thru the numerous connections from there. I recalled what a pain it was to remove the large connector the first time and as I pulled on the cable it came off rather freely. Not a good sign. So I cleaned all the contacts again and as I looked at the base of the unit I also noticed that the little rubber foot mounts were not aligned in the proper slots. The rubber mounts protect the electronics from excess vibration. One of them was actually out of the track and no longer providing dampening.

I realigned the brain unit, putting the rubber feet in the track and then I very carefully aligned the cable. I made sure the cable snapped into place and that the cable locking mechanism on the right side was fully set. It was now very difficult to tug on the cable and there was no way it was going to come loose accidentally.

At this point I'm still using the process of elimination to work my way thru the entire ignition signal path. It's hard to be optimistic when I've gotten my hopes up before.  But this is another good find and a good example of the importance of checking every little detail on a new motorcycle purchase. Particularly an old K-bike. Although the bikes are legendary for their reliability, when an intermittent electrical problem pops up you need to be patient and methodical. Or start writing checks to a dealer.