Hi, I just installed a new head gasket on my '98 yz400. It overheated due to the radiator leaking. I got the radiator repaired at a radiator shop. I started the bike today and it is overheating, the choke has to be on in order for it to run when I take the choke off I have to keep reving the bike and it pops, flames out of the exhaust, pipe turns cherry red. Any suggestions? Maybe I installed the wrong headgasket?