Leaking gas and gas mixing with the oil - 1990 Yamaha YX 600 Radian

The problem you are having is more than likely the carb boot which attaches between the head and the carb. that year up to approx. 1994 Yamaha had very weak rubber, sudden back fires or vibration would crack the rubber causing a broken seal which in turn would cause excessive flooding. Replacement boots are of far better quality which eliminated this problem. Would also be a good idea to purchase a carb kit , appox. 25 bucks, which includes o-rings needle and seat valve. Just incase that this maybe a combination of your problems.
Hopefully this helps you out, Let me know other wise, I am thinking of quiting this site being that everyone runs with the info posted, and never returns to grade you on the info they have recieved .

The problem you are having is more than likely the carb boot which attaches between the head and the carb. that year up to approx. 1994 Yamaha had very weak rubber, sudden back fires or vibration would crack the rubber causing a broken seal which in turn would cause excessive flooding. Replacement boots are of far better quality which eliminated this problem. Would also be a good idea to purchase a carb kit , appox. 25 bucks, which includes o-rings needle and seat valve. Just incase that this maybe a combination of your problems.
Hopefully this helps you out, Let me know other wise, I am thinking of quiting this site being that everyone runs with the info posted, and never returns to grade you on the info they have recieved .