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Discussion Starter #1 (Edited)
Hello everyone: listen to this one: I was at a track day in South Carolina on the 21 of October....my F4 1000 stayed in my trailer overnight when the temperature went down to 44 degrees. In the morning I took the bike out to go ride and I notice that the bike kept leaking gasoline from the bottom of the gas tank, non from the overflow pipe at the bottom of the bellypan. I do have to point that the night before the tank was overfilled a little bit but still the excess should have been discharged from the little tube into the bellypan, instead the leak was coming from the very bottom of the tank; even funnier was the fact that if I opened the gas cap, the leak would stop; close the cap again and the leak would start again. Keep in mind the bike was under the sun at this time while the gas tank was cold cold cold from the night. I came home and took the gas tank apart and found out that there is a part under the tank called "webber" (on picture number 3 it is that small circular part with a small pipe that sticks out of it and indicated with a light red arrow). This part did NOT have any rubber tubes attached to it. Would anyone know how to explain all of this? Is there a rubber pipe that actually needs to be attached to this "webber" thing or is the phenomenum due to the simple pressure built in the gas tank result of the change in temperature between night and day.....or what????? Thanks for anyone's help on the above.
Alfredo
 

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Ah! thats the fuel pressure regulator, 'Webber' make fuel system components, it doesn't have anything attached to it on the MV, its a common part used in other applications where that tube would connect to the inlet manifold to alter the fuel pressure under different engine conditions to assist with easier fuel mapping, sounds like the internal diaphragm has gone, you'll need a new one there non repairable :)
 

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alfredob said:
are you talking about a new "webber" piece or....what?
Yes.........you need to order a new fuel pressure regulator, part number 18 on the attched PDF
 

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You don't actually say where the fuel was coming out. I doubt that the fuel pressure regulator (the "Weber" piece) is the source. I suspect that there is nothing wrong, and that as the fuel heated up and/or the bike was moved, it started pushing out the overflow. The small tube below it in the third picture seems more likely. There are two "overflow" tubes. One is the actual overflow from around the filler, the other goes from the highest part inside the tank. Only one of those has a tube on it in your pictures.
 

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Discussion Starter #6
the fuel was coming out from the very bottom of the gas tank....to make you understand the leak was coming from the top of the engine and falling on top of the clutch; in my opinion "mikef4uk" is right on the money...thanks
 

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alfredob said:
the fuel was coming out from the very bottom of the gas tank....to make you understand the leak was coming from the top of the engine and falling on top of the clutch; in my opinion "mikef4uk" is right on the money...thanks
Thanks! but I would check the obvious first, people have had leaky fuel pipes etc, this would be the 'first' leaky fuel pressure regulator. :)
 
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