When I upgraded to a super 6, I had to rig up a cable system as the linkage wouldn't work. With some creative thinking, I rigged up a system using a Go-Cart cable. I used the "Monaco" cable. Googling go cart parts will yield more results that may help. Good Luck
Go Kart Throttle Cables | Go Kart Brake Cables | Go Kart Throttle Cable Hardware
