Petcock/fuel flow has little to nothing to do with plug color.
The old myth that a "high flow petcock" improves or effects performance is only in the minds of those who say it.
Look at it this way and try this experiment: First fill your fuel tank. Disconnect the fuel line from the carb, open the petcock and drain the tank into a container while timing how long it takes to drain. Now compare that time with how long you could ride your bike before you run out of fuel.
I will guarantee you that the tank will drain in a whole lot less time that your engine could burn it.
My point being that the engine can only consume so much fuel per hour. Increasing the flow will have no effect on how much the engine can use. The carburetor float and needle valve controls the fuel flow, not the size of the petcock orifice..
As long as the petcock/fuel line will flow a steady stream, not dripping, it will deliver sufficient fuel.
With this in mind I can only assume that you were running extremely lean do to a lack of fuel in the carb because of the "partially restricted" petcock. That would explain a lean reading on your plug color inspection.
Tom
The old myth that a "high flow petcock" improves or effects performance is only in the minds of those who say it.
Look at it this way and try this experiment: First fill your fuel tank. Disconnect the fuel line from the carb, open the petcock and drain the tank into a container while timing how long it takes to drain. Now compare that time with how long you could ride your bike before you run out of fuel.
I will guarantee you that the tank will drain in a whole lot less time that your engine could burn it.
My point being that the engine can only consume so much fuel per hour. Increasing the flow will have no effect on how much the engine can use. The carburetor float and needle valve controls the fuel flow, not the size of the petcock orifice..
As long as the petcock/fuel line will flow a steady stream, not dripping, it will deliver sufficient fuel.
With this in mind I can only assume that you were running extremely lean do to a lack of fuel in the carb because of the "partially restricted" petcock. That would explain a lean reading on your plug color inspection.
Tom
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