just to add a little info to what the others have already said about this not likely being the cause of your problem. When I removed mine and took it apart to see what had happened there was a thin tear in the diaphragm probably about 20-30mm long. I bet I rode it for a few years before it fouled the plug enough to matter, the fuel smell after shutoff had been around for a long time with no other symptoms, the bike performed perfectly normally up until the plug fouled. It eventually led to slightly decreased fuel economy, which is what caused me to investigate further when I noticed the fouled plug.
Article [11] ST1100 - How to do an emergency bypass of the fuel valve
Long(ish) story short; the issue was that the fuel filter had probably never been replaced. She's a lot happier with a flushed filter (new one on way). The fuel shut off valve is in working order, though I found the little one way valve in the side casing was a little bit sticky. It will stay off until new lines arrive (I'm not the first to remove it and the refit by the last person wasn't ideal). I found that the sub filter was disintegrated, I'll be looking for threads with experiences and opinions regarding this.
Man, I do a lot of long distance riding where I'm miles from home. I REALLY appreciate topics like this that give me a heads up to potential problems and how to fix them. This will be the first mod I make and will remove mine as soon as I take the bike out of cold storage. One less thing to go wrong...go wrong...go wrong.
Mega thx Michael for sharing that bypass procedure; outstanding pics!....I'm paying the price for not already knowing this before mine failed 37 mi so of KC,MO last week. If I had known this, I would have likely made it to Denver as planned. I also lacked the hex key needed to remove the tank cover when it failed, so I was stuck(5 hours, 95 degree heat, waiting on AAA tow to arrive). I have already ordered replacement petcock, but can see here I'm better off to just by-pass the thing completely...thinking I'll install the a 2nd filter in it's place and just plug that vacuum line....this forum is priceless!
A few rides ago, I noticed my gas mileage seemed to be dropping. Normally I've always gotten close to 50 mpg. Last week I barely got 170 miles out of a tank of gas, instead of the 300 that I'd been getting. So I removed the vacuum fuel valve then took a 235 mile ride from Vernal over Wolf Creek pass towards Kamas and back. When I got home, I filled it up again. Took 4.3 gallons to do the 235 mile round trip. 54.6 miles per gallon.
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greetings all, wanted to add my valve removal story to this thread. it was indeed easy to bypass the valve, and the st started right up,
but now i have a new fuel leak(?) under bowl of carb that has that odd idle adjustment cable connected to it.....i may have caused the leak pulling on hoses bypassing the valve...i had to replace existing hose with slightly longer hose to reach between fuel filter and pump outlet...I'm wondering if maybe just a choke overload issue and not a real leak, fuel getting into vacuum lines like others have seen....
plan to do a little digging in the manuals and take another swing at it tomorrow. I did seal off that small vacuum hose per the procedure to replace valve, but got a lot of other vacuum lines disconnected after removing the airfilter/housing to locate that leak(overflow?)......no way i'm putting that weird petcock thing back on....i did rebuild it, I got about 1000 miles out of rebuild....maybe ethanol not so good for seals in petcock, who knows, but the design is flawed and the bike runs better w/o it, so it's in the can already.
happy trails!
but now i have a new fuel leak(?) under bowl of carb that has that odd idle adjustment cable connected to it.....i may have caused the leak pulling on hoses bypassing the valve...i had to replace existing hose with slightly longer hose to reach between fuel filter and pump outlet...I'm wondering if maybe just a choke overload issue and not a real leak, fuel getting into vacuum lines like others have seen....
plan to do a little digging in the manuals and take another swing at it tomorrow. I did seal off that small vacuum hose per the procedure to replace valve, but got a lot of other vacuum lines disconnected after removing the airfilter/housing to locate that leak(overflow?)......no way i'm putting that weird petcock thing back on....i did rebuild it, I got about 1000 miles out of rebuild....maybe ethanol not so good for seals in petcock, who knows, but the design is flawed and the bike runs better w/o it, so it's in the can already.
happy trails!