It is a given that machines are fallible devices, and that the older a machine gets, the more likely it is that something will indeed fail. In this particular case, it was the throttle cable of my 1973 Europa Special that decided to break at the start of the second lap of my third run at the Utica Autocross. At first I was greatly annoyed, but then I realized that after all, this was the original cable and that it had been in service for 27 years. I also realized that if it had to let go, better here than late at night in the middle of nowhere.
The cable broke at the carburetor linkage, which was good. But the broken end was badly frayed and too short to reach the pivot bushing on the linkage, which was bad. Jack Martin's friend Larry Ostdick offered me a length of stranded copper wire, so I striped the insulation from the wire, and then used the barrel from a ring terminal to crimp the stranded copper wire to what was left of the throttle cable. The copper wire was then fed through the pivot bushing and secured with the screw. It worked fine and got us home without drama, although I was careful not to tempt fate with any heavy footwork.
Back home I had a new throttle cable which I apparently had bought some time ago for just such an occasion. However, in the cabin, the cable assembly was sandwiched between the fiberglass bodywork that runs alongside the chassis and the interior carpeting. There did not seem to be a way to remove the old cable assembly without damaging the carpet, so I simply pulled out the old cable wire and installed the new wire into the old sheath. The bare end of the wire was tinned so there was no problem feeding it through.
I think the old cable broke because of the cheap design of securing it to the carburetor linkage. The cable slips through a hole in a pivot bushing, and is locked into place with the end of a screw 90° to it. The end of the screw mashes the cable and begins to cut into it, fraying and weakening the wires. To help avoid this, I made a protective sleeve 3/4" long made of 1/8" OD aluminum tube, obtained from the hobby store. I flared one end of the sleeve slightly and slipped it into the hole in the pivot bushing. Then I passed the cable wire through the sleeve and tightened the screw. Now the sleeve spreads the load over a wider area of the cable. We'll have to see if it lasts another 27 years.
