About 6 months back I bought a 93 Nighthawk from my neighbor. Everything had been running great until I started to prepare the bike for a long trip.
Recently I have encountered a problem where the bike intermittently loses power then lurches forwards. This happens a few times then the bike will either stall or require choke to run. I took the bike to a mechanic who diagnosed the issue as dirty carbs. I got the carbs cleaned out and the problem still occurs. Called the mechanic back and he said he'd taken riden it around with no problems, but if I am still having the same issue it could be the fuel petcock and/or debris in the tank. I thought the issue might be electrical (bad coils or loose connections), but as I took off the gas tank today, fuel poured out of the petcock even though it was set to the off position. A couple of minutes later I picked up the tank and more fuel dripped out. If I am not mistaken, there should not be any fuel in the petcock as the cb750 has a vacuum operated valve. I disassembled the petcock and it was full of fuel, but there is not visible damage to the rubber gaskets inside. Are there any other issues that could be causing the lurching and power loss or should I go ahead and replace the petcock?
