My experience has been that a coil will cut out all together or work intermittently usually cutting out or breaking up when it gets hot after a few laps. I don’t know if it’s the best way but you could put on a new coil and see if it goes faster. Not sure about K80 but a KT100 is a 10:1 ratio primary to secondary coil on a resistance test.
FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience