My classic 350CC is 4 days old. I have experienced an issue that I am riding the bike the engine cuts out. The fuel tank has close to 6 liters of fuel and set the fuel knob to ON. I immediately changed the fuel knob to Reserve and the bike started running as usual without any problems. Then I changed the fuel knob to ON and bike started working for say 2 to 3 KMs and then bike started to stop. I had to immediately move the fuel knob to Reserve for it work.

Anyone that can give me any advice on what to do?

  • Are you sure all the lines from the main tank are good? Seeing that it runs good from reserve but not the main fuel cell tells me something is wrong with the area between the main cell and the carb.
    – Granny
    Jan 15, 2018 at 9:32
  • Have you checked this question.mechanics.stackexchange.com/questions/27593/…
    – DhKo
    Jan 16, 2018 at 13:03

1 Answer 1


If the engine runs in RESERVE, but no ON, then it sounds like the petcock isn't allowing fuel to flow when set to the ON position.

Check the hoses going from the petcock to the airbox. There could be a vacuum line disconnected that's preventing fuel flow when set to ON with the engine running.

Check the fuel lines from the tank to the petcock. The normal line that's used for ON might be blocked or clogged.

Finally, check the petcock itself. If the internal diaphragm isn't in good working order, it maybe sticking closed even when a good vacuum source is supplied.

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