My 97 Harley Softail Custom is leaking gas out of the carburetor when running. This i know is due to having a vacuum petcock which is why it doesn't leak when the bike is off. I pulled the carburetor thinking the float or needle wasn't seated correctly but I tested the positioning and seal while cleaning it and they work just fine. I recently laid my bike down on the side away from the carburetor and had to remove the petcock in order to get the gas tank repaired. Since reinstalling the tank and petcock, this problem has come up with leaking gas. Is there anything that could be causing this gas leak from the carburetor besides the float and/or needle? Could the petcock somehow be forcing gas into the carb?

 

It sounds as if your vacuum petcock is working correctly, but there is no way it can add pressure to the fuel in the carb, so I suggest we can set that aside as a possible source of the problem. I also don't believe the other things, such as tipping the bike over, can have any effect. The notable thing is that your bike is 22 years old and during that time various perishable parts inside your carb can deteriorate, including the float needle. You can however buy a repair kit with all the parts required to do a complete rebuild and I recommend you do that first.

 

Don`t buy any el cheapo parts for the carb, especially the needle...As Graham says, it may just be worn out parts at the needle/seat.

These guys have what you need:

https://cv-performance.com/