silicone disk cam out of gas cap

Joined
Aug 26, 2013
Messages
115
Location
Dewitt, Michigan
Bike
1997 ST1100
In my zeal to clean out the fuel tank I managed to blow out the little silicone valve disk from the fuel cap. I removed the rubber gasket and soaked the gas cap in ZEP to clean up some surface rust and grunge. It was very dirty. After a thorough rinse it looks like new. I used compressed air to blow out the excess water and dry it out and a little cream colored silicone disk on a stalk popped out. It came out from the little hole in the center of the cap if you look at it from the bottom. Does anybody know which way this thing goes back in? I?m thinking it goes in ?head? first with the little tail following. The service manual I have does not go into that much detail. Anybody else ever have this happen?
 
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Eagle59
Joined
Aug 26, 2013
Messages
115
Location
Dewitt, Michigan
Bike
1997 ST1100
It looks like the internal valving is a bit more complicated than a simple silicone disk. A bit of digging found a rather detailed tear-down procedure for the gas cap on another ST site. Another weekend project.
 

Mark

Gotta make tracks
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I agree Dean! :)

Very nice writeup on doing a complete rebuild on st-riders.net.
 
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Eagle59
Joined
Aug 26, 2013
Messages
115
Location
Dewitt, Michigan
Bike
1997 ST1100
That's exactly what I did. I carefully unrolled the crimp on the outer gas cap shell and was able to remove the inner housing. That gets access to the inner workings and valves. Re-inserting the wandering silicone disk was possible. It was a good excercise because there was a lot or crud and softened up varnish in the nooks and crannies of the cap and valves. There was also a squished O ring that will now get replaced. I probably wouldn't recommend a tear-down of the gas cap as a preventative measure unless plugged-up or otherwise not functioning. If it works, leave it. I'm kind of glad I had the excuse, though self-inflicted, to get in there and clean it up. With the rest of the fuel system now totally rejuvinated, the cleaned up gas cap is a nice finishing touch.
 
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