Discovered an very small hairline crack on my yamaha 250 today while replacing a couple worn out components. Is there a decent quick fix so I can ride tomorrow? I have a friend who will tig weld it after I get back, but for the short term I need something. JB Weld or similar maybe? Givin that I am pretty sure the crack has been present since I have had the bike running (only had it about a month, done about 3 rides on it) would a leak in the expansion pipe cause a rich or lean condition? Only reason I ask is the bike is jetted to rich for my elevation and runs richer than I would like.