Hello new member, I have a helix 150cc, my son was driving one day and it just stops. Motor was still running but it will not go into forward or reverse, cables are fine, it’s like its just not engaging inside transmission? Suggestions?
Follow the shift cables from the shifter to a plate on the transmission. Have someone move the shifter while you watch & see if the shifter/swivel plate moves with the shifter. Put the back of the kart on stands and run it. You may end up pulling the drive cover off, it's on the driver's side of the transmission. The variator, drive belt and driven clutch are under that cover. If all that checks out you may have to disassemble the gearbox or at least pull the cover off where reverse is. Pretty involved though. Here is a shop manual for that kart's drivetrain.