Ignition system

As I mentioned in the engine evaluation post, the ignition produced a pretty weak spark. I set out to diagnose, and hopefully cure, the problem.

I pulled off the points cover from the end of the crank and took a look at the points. They were a little dirty and pitted, but not bad at all. The condensers didn't have any leaking electrolyte, so they probably were fine.

I checked the power supply to each of the ignition coils - both were around 12.5 volts, which suggests that the wiring and ignition switch is OK. I sprayed some contact cleaner in the bullet connectors and gave them a scrub with a scotchbrite pad for insurance before reconnecting them.

I disconnected the points from each coil and checked the potential voltage at the ground side - this would give a good comparison of coil resistance and the condition of the connections on that side of the coil. They were fairly equal at around 12 volts, so the coils were apparently in solid condition.

I cleaned all the connectors in the system and figured the next step would be cleaning and setting the points. Hopefully that would let it produce a nice hot spark.

I disconnected each set of points and gave them a quick brush with some 320-grit sandpaper. Then I checked the gap (.040, within spec) and gave them a blast of brake cleaner to get rid of any residual oil and dirt.

The result? A good hot spark. Maybe not as good as a modern bike or car, but certainly good enough to get this beast running again.

While I had the system apart, I also bought some new B8ES plugs from my local bike shop, and gave the ignition cover a good polish on the bench. I'll have to do something about the other engine covers eventually, but at least this one looks good!

With the new plugs in and the ignition system squared away, I sprayed some carb cleaner down the throats of my newly-rebuilt carbs and cranked it over. I was rewarded with a few second of (loud) idle through the naked exhaust ports. This thing is just about ready to run.