No spark drive side...

So I am almost ready to start the bike after almost 25 years in the barn.

Every thing works now after replacing the key switch and cleaning twice the handlebar switches.
Even the hi beam flash button and hi beam indicator lamp work fine. Brake lamps from cable front and rear brakes too. Gauge lights too. Cable front brake switch and rear brake switch are working good too.

But he drive side spark plug does not fire. The timing side is fine. I switched the yellow/black and white/black wires at the coils/condensers and plug and then the drive side did fire that plug. So that tells me that the drive side coil is OK.

I checked all the connections from the coils and condensers and spark plugs and wires. The drive side does not fire.

What is left to check?

I want to check the white/black wire from the points igniti0n to the coils tomorrow.
What else is left to check?

I hate electrics!

Could be something as simple as a bit a crud, or rust around the points.

Take the cover off and have a quick look - it's the one on the right (near the front of the bike) for the drive side.

You may even get lucky and find the black/white wire is off!

Take the points cover off and verify that both contact breakers open and close as you slowly turn the motor over. If you have a voltmeter you can verify that there is -12 volts across the points when both are open, -6 (ish) volts across the open one when one is closed, and zero across the closed set.

Be aware that when a points set opens there will be a couple hundred volts across them for an instant, and that can be painful if you're unfortunate enough to be touching them.

Got it!
Thanks for the suggestions guys.
One of those 'How did I miss that' moments.
For you sharp eyed ignition points users, here is what I found inside the points cover.
Can you see why the drive side did not spark?

Bob Z. said:

Can you see why the drive side did not spark?

Click to expand...

Edit: The RH points wire terminal appears to be directly under the nut (although the LH 'BY' set is normally used for the drive side cylinder on Commandos* according to the factory manual, as both wires look BW) :? :


*(Triumph did this the opposite way, the RH BW points being the drive side set).

The plastic cam follower is broken?
Long time since I looked at a set of points! I give up.

Looks like the wire connected to the points set on the left (closest to the rear of the bike) is not installed correctly. The terminal is not straddling the spring and is possibly contacting the hold down screw?

Yes, the set of points on the right of the photo (the one with the shortest wire) has the white plastic spacer installed incorrectly with the metal tab on top.
LABs illustration shows the assembly.
The yellow tracer on the wire has faded to black.
I didn't know that the left/right of the points in the cover were handed for drive and timing side cylinders.

The bike started yesterday and the peashooter exhaust sounded great, and no rust through that I expected.