Cracked vent tube

I have had some issues tuning my carbs but I have gotten the bike running quite well at times. This morning after cleaning the pilot circuits I went for a ride. The bike ran like crap and cylinder 1 was non responsive to idle mixture adjustments.

I pulled the carbs (vm26ss) to inspect the circuit and noticed that the vent tube that hangs out of the carb body has a vertical crack(NOT THE OVERFLOW TUBE).

Would this create my rich condition on that cylinder? How does this tube effect the pilot circuit? How can I replace, repair just the tube without replacing the carb body?

calvin17d wrote: I have had some issues tuning my carbs but I have gotten the bike running quite well at times. This morning after cleaning the pilot circuits I went for a ride. The bike ran like crap and cylinder 1 was non responsive to idle mixture adjustments.

I pulled the carbs (vm26ss) to inspect the circuit and noticed that the vent tube that hangs out of the carb body has a vertical crack(NOT THE OVERFLOW TUBE).

Would this create my rich condition on that cylinder? How does this tube effect the pilot circuit? How can I replace, repair just the tube without replacing the carb body?

With engine idling, could spray WD40 on the crack to see whether the rpm changes or adds smoke to the exhaust, which may help determine whether there is undesirable ingestion of outside air through the crack into the normal fuel mixture being provided from the carb to the combustion chamber.

But would expect such ingestion to result in a "leaner" condition instead of a rich condition.

A non-responsive idle mixture adjustment often indicates an obstructed passage in the pilot circuit.

Good Fortune!