Honda shadow vt600 gas leak in oil tank


  • Hi everyone,

    I have a '98 Shadow with a single carb that's leaking gas into the oil tank. After discovering this, I had a mechanic rebuild the carb, including cleaning, new gaskets, O-rings, and the needle valve at the bottom of the carb. I trust it was done properly(before the rebuild i had leaks from the bottom of the carb and constantly smelled gas when I was around the bike, but after the rebuild there are no leaks from the bottom of the carb).

    After flushing the oil a couple of times and refilling half the oil tank, I left the bike with the petcock ON for 24 hours. This morning, I noticed the oil level had risen and smelled some gas in it.

    The bike still runs the AFP line from the tank to the carb. My mechanic mentioned the diaphragm might be broken, which is a recalled Honda part, and this could allow gas into the intake manifold.

    From what I understand, if the AFP diaphragm is broken, the bike usually won't start.

    Could a faulty AFP diaphragm be causing the gas leak into the oil? If yes, the only way to solve this would be to bypass the afp and go straight from the gas tank to the carb right?

    Hope I've been clear enough, I'm new to motorcycles, so please don't kill me :D



  • @gabfrassanito The AFP was recalled by Honda. The afp can do two things is its not functioning right.

    1. allow fuel to flow into the carb unchecked. 
    2. block any fuel from reaching the carb. 

    so your afp is likely broken, heres a video on getting rid of it! - https://youtu.be/S0fYNWPkwp0?si=wn6aN26Rba9zpol5
    it sounds like your floats are not seating or the float heigh is set incorrectly. So id pull the carbs and do a test with fuel before you put them back on the bike. hope this helps man! 

     


  • Thanks TJ!

    how can i do the test with the carb you mentioned in the last sentence?


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