Belt Go Kart Seat

Help seatbelt four go-kart?
http://kartbuilding.net/wooden_go-kart_p ...

Yes, I do improvements to make it safer, but I need more

I made this basket it goes over 40 km / h and I need ideas safety restraint

I put a plastic seat on the i pretty well, but STRT folding crshed after hitting a curb and my friend was robbed and got 20 points and a broken arm bad

HELP PLEASE

buy belts and bolts, or welding either. you need support

ur best bet would be to get a racing seat with a harness racing
they work better than traditional safety belts