When I bought the bike and first filled it up, fuel leaked from the right hand carb, after taking off the float bowl and tapping the float it stopped.
Since then I (with the help of a retired mechanic) have replaced the gasket, replaced the float valve which had a groove in the rubber tip, checked the float didn't have fuel in it, and adjusted the tab that presses the valve. All seemed good, leak stopped, until today on my first long ride when after an hour I stopped for lunch and when I came back to bike fuel was p**sing out as badly as it ever had.
It seemed to be leaking from a small pipe/tube in the middle of the carb. When I turned the tap off and waited for it to empty, then turned it on again, fuel came out somewhere else, (nearer the side with the float valve).
I had the same deal. After the rebuild kit, it still happened. Against the advice of my mechanic, I filed the top of the float ever so slightly, decreasing the chance for the top of the float to come into contact with the dome of the carb. 2 years later, no leaks. And always - always - turn off the fuel when not mobile ;>)
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Re: BMW R80 1987 Leaky Bing carburettor…
Type in "R80 carb rebuild kits" in google. There's a few sites that have them on offer. Generally just the diaphams, gaskets and O-rings.
Float level may be set too high on one side allowing it to overflow too.
Had a similar issue on my R65. Just got in the habit of putting it on the centre stand and turning the fuel cocks of when not mobile.
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Its probably the float sticking in the carb, not shutting off the fuel flow when the bowl fills to the proper level and the leak is really gas flowing out the overflow.
Disassemble the carb and gently clean the needle and seat with Scotch Brite oven pad. Some needles have a rubberized tip and if so, do not attempt to clean with the pad, but inspect it for a worn 'ring' around the perimeter that is failing to seal off the flow of gas into the bowl through the seat. A replacement needle is required if in fact it looks indented.
IF you have already disassembled and cleaned the inside of the carb, you may have jeopardized the intergrity of the bowl gasket. Get some gasket sealant at the local auto parts store and disassemble the carb again. Use a toothpick to run a thin...thin...thin line of Form-a-Gasket sealant around the perimeter of the bowl and GENTLY reassemble the carb. A thin line is a MUST as any excess can be squished inside the carb and possibly block an idle jet of inhibit the action of the float.
It may be ok , but many bikes flood when sitting over night and fill the sump with fuel. if the carb float doesnt quite seal.
Not sure about epa , I think it shouldnt be a problem unless carb overflows and drips on the ground, during the inspection.
First take that 3 rd carb off, the needle and seat is stuck in the open position, the float may be rubbing on the inside of the float bowl cover, or the float setting is out of adjustment (too rich) either way the fuel to the bowl is not shutting off as it fills, the needle and seat must be forced shut by the gas filling the float chamber raising the float and pushing the needle up into the seat. Sometimes the float has been compromised put it in a cup of gas to ensure it floats and is not a sinker. reassemble and check for the fuel over flow if it still over flows your problem has not been solve this issue must be adressed first for the bike to run right otherwise that one cylinder is going to foul and the bike will never run right.
The hose does not need to be connected anywhere. It could be a battery, crankcase or carb vent hose. It is fine as is. The problem is a stuck carb float or a carb float out of adjustment. Unfamiliar with BMW, I assume you have carbs and not fuel injection. Remove and clean the offending carb.
Probabilly a stuk carburettor float or needle.
Try to solve this problem to gently tap on the carburettor bodies. If this doesn't help you have to clean out the carburettors, and/or replace the float neeldes
so you have a hole in your tank somewhere. or leaky fuel **** gasket. firstly you need to find the leak. or is your gas just flowing right thru your carbs and out the overflow? shut off fuel to eliminate carbs. if it stops leaking then its probably gummed up carb floats. use Berrymans B12 fuel additive this will work into the carb and hopefully break down the gum. or strip and clean them by hand with a good spray carb cleaner. or remove air cleaner and spray directly into carb and let sit for a few days.
if it's a gas tank leak then you will have to get it lined, (liquid sealer) so long as the hole is not too big. if it is then drain and dry the tank, get it welded professionally or patch it with a filler or fiberglass and then get it sealed, i used my local radiator repair shop to het mine done.