Hey guys. Just picked up a 93 750sx. The top end is fresh and I was told the carb isnt stock.. I'm having some problems though. It seems to be running rich. The past few times Ive had it out Ive burned a whole tank of fuel in less than 90mins. Is that normal? The ski is a slug and doesnt start running good untill the last half hour of riding then it runs very strong if that makes any sense. The plugs looked fouled the first half of the tank then after I finish the second half the plugs look good.. The oil injection has been removed and I'm running yamalube 50:1. Any ideas please.