I’ve seen several references here to making up a new throttle cable from a bike brake cable. Straightforward enough, except for the termination of the end of the cable you cut. Some used adjustable stop collars and had problems with them coming loose at inopportune times.
I re-used the rear brake cable from my last bike overhaul and purchased a length of housing and four housing ends from the local bike shop. The ends have a short guide section at the tip that gives the cable a clean entry to the housing, so they’re important. I cut the housing into a short and long piece using a good pair of diagonal wire cutters, and threaded the pedal end, short housing, adjuster, and long housing onto the cable. The existing cable end fits perfectly in the clip on the pedal arm.
For the carb end, I found some aluminum 1/16" cable stops at the local hardware store. I trial-crimped a collar onto some unused cable and was unable to move it, so it should hold. I used the round stop collar as the primary stop and backed it with a ferrule, with two holes (intended to join two cables I guess). I doubled the cable back through so it absolutely won’t come off. I used a small washer and two short pieces of shrink tube, one over the other, to retain the cable in the bracket on the carburetor. (See photo.)
After trial fitting and careful marking, I crimped everything, shrank the tube, and installed. The pedal is very smooth and does not bind at full depression like the (40 year??) old cable did.
I’ve found that in applications that require a very long cable (power window cables, etc), a cable from a tandem bicycle (bicycle built for two) is the longest cable around.
In an emergency the metal internal bit from the type of electrical domestic terminals which we used to call “chock-block” makes a good cable-end nipple. Just slice one off the block and remove the plastic outer bit.
I left the original soldered nipple in place and used that as the carb end. Taking the inner out from the outer I slipped a piece of thin alloy tube (&) over the inner right along the whole length until it contacted the fixed nipple & then crimped it with a wiring crimper to keep it in place. This was to fatten up the carb end so that it locates in the slotted hole properly. I cut the outer to match my original throttle cable, keeping the short bit with the adjuster in use.
(&) I think this was the outer of a small pop-rivet.
I had to buy a pair of brake cables & I’m pleased to say that today, I used the other bit of outer brake cable to mend my push-me/pull-me heater valve control cable.
Any decent bicycle shop will have the cable on a spool as well as the housing/sheathing and can make up a cable any length you want. I think a gave the local shop $15 for a custom made one 4 years ago.