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Comet GT650 possible fuel leak

Discussion in 'Technical and Troubleshooting Torque' started by TheMav, Nov 30, 2013.

  1. I have a 2008 Hyosung GT650 Comet. I usually fill it all the way to the top and never noticed any fuel leaks when I am riding however when I dropped the bike on its side I saw fuel coming out of the fuel tank cap. Is this indicative of a leak?

    I am worried about rain getting in, it ran very rough yesterday after the rain.

  2. If it is running rough I would say that the drop on the side has more to do with it than water in the fuel. I doubt enough would ever get in to cause any noticeable problem, unless the leak is very severe. I am unfamiliar with the Hyosung but like all vehicles these days I would expect that the cap should not vent for safety reasons so could be worth looking at the cap and seal. The tank will have a system for the tank venting with a safety valve in it and well away from the rider.
  3. Check the air filter. Most bikes have the crankcase breather feeding into the bottom of the airbox, and when bikes have a little lie down sometimes oil goes up the breather and contaminates the air filter.
  4. The tank vent is in the cap.

    If you drop it it will leak there's a rubber flappy thing to stop the water getting in.
  5. Thanks guys, I actually dropped it a while ago, not because it rained.

    Haven't started it in about 2 months so I assumed it was due to bad fuel. I replaced about 90% of the fuel (by using it up) and it seemed to run a bit better but after all the rain yesterday it started running rough again.

    Will check air filter and continue to put fresh fuel in. Thanks for confirming tank vent in the cap.
  6. Problem: Bike leaks when dropped on its side.

    Solution: Don't drop bike on its side.
  7. Actually the problem was the bike running rough

    Think I nailed it down to a spark plug which someone fitted without the end cap... spark plug.

    Now for some new spark plugs!
  8. check the overflow pipe is still attached to the top of the tank. they're notorious for breaking off and hanging inside the tank. means sometimes the fuel can slosh out under heavy braking.
  9. Cheers, turns out the spark plugs are supposed to be like that

    Might need to give the carbs a clean as well...