215Guy
CB750 Member
Working on a 1981 CB750 Custom. Got the bike recently and a couple of the carbs would overflow with the gas on. They would stop after tapping them, but would start again intermittently. I was able to run the bike briefly but then took the carbs apart to clean them. Replaced the gaskets and jets from a rebuild kit. Got them back on the bike got it started, everything sounded great. However carbs 3 and 4 seemed to be leaking gas from the seal of the float bowl. I took them back apart, replaced all the bolts holding the bowls on with allen heads so that I could tighten them up without worrrying so much about stripping them. I also inspected the gaskets and decided that the old ones, even though they were a little worn, were still better than the low quality ones that came with the rebuild kit. put the old ones back in, no leaking from the seals anymore. However, the overflows are back to spitting gas, and it seems like its actually gotten a lot worse. The floats seemed like they were in good shape, and with the carbs apart seem to move freely. But especially in carb #1, there is definitely nothing stopping the flow of gas into the bowl. It sounds like its just a cleaning issue, but I just did that, so before doing the same thing over again, I wanted to see if anyone had any other thoughts on what it could be. Thanks for any help.