How To: Kickstarter pin
Burman gearboxes were used by Ariel, Vincent, AJS, Matchless, Panther and other manufacturers from the 1920’s through the 60’s. They were decent boxes, and took the power of a Red Hunter, Square Four, early Vinnie twin, 7R, etc. My only complaint of them is that the early ones tend to be a bit tough to nick into gear without a strong boot and a resulting ‘clunk’ noise (much like a /2 or /5 BMW). Double clutching is required for smooth shift, especially when shifting down.
The early models did not have a folding kicker pin (the part with the rubber that fits into your boot heel), so it stuck out sideways even when it wasn’t being used to start the bike. It was threaded onto the kicker arm, but tended to come loose due to vibrations. If it didn’t unscrew itself and fall off into a ditch, the kickstart after the next stop would typically bugger up the threads… Hence there is now a market for replacement kicker pins. The part on Kim’s Ariel was die-cast, with a parting line running across the threads in two places. It never screwed in tightly, and wasn’t going to stay in place. So we quickly made up a new one:
A simple bit of turning work, starting with about $5 worth of 12L14 bar from McMaster Carr. This is mild steel with Lead added to make it easier to cut; The lead lubricates the surface as the tool cuts into the steel.
In this view, the threads will be on the right, the rubber will fit on the left. The live center is the tapered part that is supporting the right end of the workpiece. I was able to do the whole part in one setup, which keeps the various surfaces of the finished part all concentric to each other. (that is overkill for a simple kicker, but it is good practice).
1. Raw material. 2. Finished Part. 3. Bad die-cast reproduction part.
After the lathe work, a quick session on the mill cut the two flats which are required for the wrench during installation.
You’ll see that I made the threads longer than the original.
Those longer threads were used to install a nut on the backside of the kicker arm. This nut now locks the threads of the pin against the threads in the kicker arm, so the pin cannot come loose due to vibrations. Jam nuts (aka double nuts) are a great way to keep threaded joints tight in many places in bikes and other machinery. Try it on your rear brake rod.
A happy wife at the Legends Show a few years ago.
Want to fit a Burman 4 speed into your 3 speed Indian Sport Scout or 741? look here.