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post #1 of 5 (permalink) Old 07-13-2009, 10:25 AM Thread Starter
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Phantom Gas Syndrome

Many of us have had the problem of the bike cutting out randomly when we get at or below 1/2 tank of gas. Venting the tank or letting it set for 15 minutes allows it to start again. Since this seems to be some sort of vapor lock, I went for the easiest solution. I took the gas cap apart and removed the two stacked plastic units containing the rubber diaphrams. I put the gas cap back on and haven't had any trouble with the engine cutting out since. I hope this helps restore some faith in a great bike. The engine now runs great no matter where the gas level is.

I hope this helps
Mike G
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post #2 of 5 (permalink) Old 07-13-2009, 09:37 PM
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I got Phantom Gass Syndromed the other night. First time for me. Thanks to this forum I knew what to do to get running again. It was late at night 25 miles from home in the middle of nowhere. Popped the cap and she ran fine all the way to the nearest gas station. I decided to tear my gas cap apart today to "fix" the problem. I'm down to the plastic pieces with the diaphrams. How do these come out? Can they be cleaned and reinstalled? If so, what's the process and what do I use to clean them. I'm assuming they're there for a reason, so I'd like to put them back.

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the background was digitally blurred to make it look like I'm going really fast.

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post #3 of 5 (permalink) Old 07-14-2009, 12:09 AM Thread Starter
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The plastic pieces with the diaphram just lift out. They are stacked one on the other with o-ring gaskets inbetween. So many people have had this problem that I don't trust the rubber the diaphram is made out of so I don't think cleaning will help. They look like they may help stop the flow of gas if the bike is laid down. Its your call. After having been stranded several times and wasting 2 sets of plugs, I don't mind leaving them out to get the dependability back.

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post #4 of 5 (permalink) Old 07-14-2009, 10:25 AM
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for me this problem occurs when im going on a slight incline and im just under 1/2 a tank and my bowls run dry in that short amount of time,
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post #5 of 5 (permalink) Old 07-16-2009, 04:23 PM
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I started experiencing this problem also about 2 months ago. I notice Mike G just pulled the plastic pieces with the diaphragm out and this fixed the problem.

Has anyone else done this and what exactly does the diaphragm do? I thinking of doing the same to fix my problem.

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