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Low Tank Lumpyness

Discussion in 'Sport Touring' started by johnny, May 21, 2018.

  1. The ST has had this a while, and after the rebuild it is still there.

    When I fill up the bike is transformed. As the tank gets lower the lumpiness increases. I have changed the fuel filter and cleaned the inside fuel cause. I checked the vent and cleaned that all out. Any clues?
     
  2. Do you hear a slight 'hiss' if you open the fuel filler when the level is low? If so then that would point to the breather still being blocked somehow.

    I appreciate you've already cleaned the vent out but did you blow it through with a high pressure line? I had it where some stubborn dirt has lodged halfway down the vent tube and came out only when the vent was blasted through with a compressed air line.

    Just a thought as it does sound like gradual fuel starvarion. :thinkingface:
     
  3. I did blow throw with pressure and I can't hear a hiss. Thinking of taking the flange unit out and cleaning checking everything.
     
  4. Worth a shot mate. Also you could try opening the filler next time it starts to run rough and see if that makes any difference. At least it would rule out a blockage in the vent if the problem persists.
     
  5. cant remember how the vent works now! is it simply through the cap body or is there a pressure relief valve?
     
  6. If I recall correctly, it's through the filler neck/recessed seat, where there's a hole towards rear. This connects to a breather tube that exits on the bottom right of the engine.
     
  7. The Cap has an exit through the flap/key area with a sort of valve system. I cleaned it all.
     
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