When your vehicle won’t go what do you do? You check for fuel, and if there is plenty, you check for spark—that is, if you carry a plug wrench. When my mother was a young woman in 1930, she was driving her dad’s car when it just stopped. She opened the hood and looked around for anything obviously amiss. Ah, here’s a loose wire. Could that be it? She found a place that looked right and reconnected it. The car started and she was on her way. Instead of doing nothing and waiting to be rescued, she took action.
I was on my way up to the St. Lawrence River in an old Ford Falcon “bearing-thrasher”—a four-main-bearing inline-six—when the ammeter on the dash began to flicker. I kept an eye on it and, after a half hour or so, it swung hard left to “discharge” and stayed there. For whatever reason, the generator was no longer charging the battery, and I wasn’t going to go far before the battery became discharged enough that it would no longer start the engine. Bad. Don’t want.
I carried tools as a first line of defense against the junk cars I drove. With the generator in my hands, the problem explained itself. The electrical connection to the generator’s spinning armature was made by carbon “brushes,” little rectangular-section sticks of conductive solid carbon sliding in similarly shaped guides of formed sheet metal. The end of a spiral spring normally bore against the outer end of each brush, pressing it inward against the armature’s copper commutator. (When motors powering electric motorcycles or electric pedal-assist bicycles are described as “brushless,” it is because they have neither commutator nor those little carbon stick brushes to fail as mine had.)
The brushes had worn so much that instead of the springs pressing against the brushes, they had come to rest against the outer ends of the guides that held the brushes. As the brushes wore shorter, spring pressure bore against the guides instead of pressing the brushes firmly against the commutator. As the brushes pressed less and less hard against the commutator, the ammeter needle flickered.
I love coarse square files because they can be used as crude manual milling machines. I used mine to file a slot in each brush guide so the brush spring could again firmly press on the brush, completing the electrical circuit. With the generator back in place, when I started the engine the ammeter needle swung to the right, indicating charge. We were on our way again.
As soon as I was able to find an auto-parts store, a set of replacement brushes—much longer than my worn-down stubs—completed the repair.
Friend and racer Frank Camillieri went for a ramble on an old BSA single. Frank likes to move right along, and that C15 was working hard, not easy for that design. Then he heard a squeak; the head gasket was failing.
Years later, I would hear that very sound as one of the late Don Tilley’s highly tuned air-cooled Harley-Davidson/Buell V-twins blew a head gasket just at Daytona’s start/finish. Don finally adopted huge half-inch studs to properly contain the combustion pressure of his 13.8:1 monster.
But Frank was stopped at the roadside, knowing that if he rode on, the leakage would become worse until the engine wouldn’t run. He had no tools with which to tighten the head bolts. But he needed more pressure holding the head down against that gasket. Then he saw the answer, an oddly shaped piece of 2 x 4 lying by the road. It wedged nicely between the top of the rocker boxes and the underside of the top frame tube. He beat it in firmly using Paleolithic technology—a stone.
Restarting the engine, he found he could ride along leak-free at about 25–30 mph. Stopping occasionally to restore “gasket preload” by more hammering on the wedge, he was able to get home without walking.
