you can make a throttle cable out of bike cables by making the end that go in the carb here is a sorry video of how. I'm shorting the cable on the video but you can make the cable by buying a set of cables from Walmart pick out the cable that will fit the throttle twist grip tube. a shifter cable should work good for this. pull the inner cable out of the outer cable decide how long of a cable you want then cut off the excess of the outer cable. lube up the inner cable and insert it back into the outer cable you should have a lot of extra inner cable stick out now follow the video and you will see how to make the end for the throttle. I make all my cables ends
if you run into a snag let me know.