Points Make… ...

prizes! Allen sorts out the ignition for his Velocette V-twin and the timing.

My Velocette V-twin engine was progressing nicely after a week of cutting, welding and filing, the extended crank pin was ordered and would be ready in a couple of weeks, so the next job was to make the ignition system.

The standard Velocette engine has a magneto bolted onto the crankcases behind the vertical cylinder, but on my V-twin engine the rear cylinder would be inclined backwards 22.5° and run close to the rear frame tube, so there would be no room to fit a magneto. I had foreseen this in my initial vision and had already machined a recess in the timing cover to hold two sets of original Honda twin contact breaker points.

The first thing I had to do was to make the points, cam and drive shaft. To do this I first removed the Tufnol gear from the old magneto and machined up a steel shaft that would bolt onto this gear. The shaft would then protrude through a bearing in the timing chest cover into the points recess. The points cam would slide on the end of this shaft and be secured with a M6 bolt.

Then I machined a new triangular bearing plate that would bolt onto the original magneto mounting studs on the crankcases to support the other end of the shaft. With the new shaft made and the Tufnol gear pressed on, it meshed nicely with the rear camshaft gear and rotated at half engine speed. I decided that the firing order would be 315 and 405°, as this would make the engine run smooth and be easier to start because the compression strokes would be felt individually, so I would need to mount the points 202.5° apart on the points plate.