Café LeMans limped to work this morning on one cylinder.
She fired up with an even-more-lumpy-than-usual idle which told me only one cylinder was making thrust. A few small backfires and a rather cool looking bang-flame in the dawn light told me left cylinder was the culprit. Too late to do anything about it, we lumpily jerked our way to work and lumpily jerked our way home again at the end of the day.
After work we dived in to investigate. First, off with the golf clubs (don’t ask), then the seat. A quick check that gravity will suck petrol from the fuel lines with the taps turned on (yup, check), then off with the tank. Some long-nose pliers helped me eliminate likely-suspect loose wires. The high tension lead was solid at sparkplug and coil ends, as were the various wires between the coils. Rats.
This is the moment where I call in my dad for advice. OK. Not literally. But I do say ‘what would dad say?’.
And I know the answer. Start simple and check the obvious. Confirm what you think you already know.
Right. So, out with left side plug. It’s wet. Presumably no spark to burn the fuel. Connect the plug to the HT lead, hit the starter. Sure enough, no spark. As expected.
Pessimism instantly makes me jump for difficult-to-fix and difficult-to-diagnose hypotheses. Buggered coil? Maybe. I have no idea how old the coils are. Dodgy connector? Maybe. I replaced many connectors when I butchered the old girl to go café and my self confidence with electrics is a bit like my competence with a golf stick.
What did dad say? Start simple and check the obvious. Confirm what you think you already know.
I pull the right-side plug. It looks good. Nice colour. Clean.
I switch the sparkplug from the troublesome left side across to the plug lead on the right side, and hit the starter. No spark! Buggered plug? Too easy, surely.
So I connect the plug from the happy right side across to the plug lead on the left side and hit the starter. It sparks.
I clean both plugs with a gentle copper-wire brush, clean the electrodes with some wet-and-dry, blow them out with a hefty puff, then reconnect them and check again. Solid spark on both sides.
Plugs back in. Leads back on. Tank back on. Connect the fuel lines and turn on the taps. Not the seat. Not yet.
Hit the starter. All good. She revs up clean.
Seat back on and, finally, golf clubs back on. Don’t ask, I said.
A happy ending, again.
My dad’s been gone more than ten years.
But he’s still fixing my bikes.
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