Get a piece of 3/4 plywood about 1′ x 3′ and put it under your kart where the seat goes. Now for left to right you want the seat to be 1″ left of center so find center and mark it on the plywood. You might have to bend the left strut a bit, try not to kink it. Then put the seat on the wood and get in and slide/tilt around until you find a good spot as far as being forward and back but try to get more forward if it’s comfy. Mark the spot with a sharpy in the left seat strut hole. After you get that right just square up the seat and mark the right strut hole.
FAA certified jet engine and aircraft technician,
Nicholson Speedway class champion 2001,
Yamaha KT100 Service Center,
41 years karting experience