My bike was running just about perfect until i went out to start it last night, opened the left petcock and fuel started to POUR out of a small hole that is just behind the lower right corner of the bing plate on the carb. I shut the valve, went and opened the other valve and the fuel started pouring out again on the same left side. Now i don't even know how that is possible... I thought the right valve only controlled fuel going to the right carb...
I checked and both carbs have this hole. It seems factory.
This is my first BMW and first time i've had any carb issues with it.
Any idea what's going on here and why that hole exists?
Bing Carburator issue '77 R100/7
Re: Bing Carburator issue '77 R100/7
Hi Jeramy,
the fuel lines are joined together by a cross piece that goes through (under) the air filter housing.
Not sure exactly what hole you mean, but fuel will leak from the carbs if the float valve doesn't seat. Its not uncommon. You will need to take off the float bowls and remove the floats and clean and inspect the valve. Probably have some junk in there holding the valves open, or else they are worn out. Its not expensive to replace them
If you don't know how to do this you will need to get a manual. Its pretty much essential if you own an old bimmer.
cheers
Mal
ps in response to your "why" question. Excess fuel has to be able to leak to the OUTSIDE of the carbs otherwise it would leak on the inside and your motor would fill up with what's in your tank and get damaged when you tried to start it.
the fuel lines are joined together by a cross piece that goes through (under) the air filter housing.
Not sure exactly what hole you mean, but fuel will leak from the carbs if the float valve doesn't seat. Its not uncommon. You will need to take off the float bowls and remove the floats and clean and inspect the valve. Probably have some junk in there holding the valves open, or else they are worn out. Its not expensive to replace them
If you don't know how to do this you will need to get a manual. Its pretty much essential if you own an old bimmer.
cheers
Mal
ps in response to your "why" question. Excess fuel has to be able to leak to the OUTSIDE of the carbs otherwise it would leak on the inside and your motor would fill up with what's in your tank and get damaged when you tried to start it.
Re: Bing Carburator issue '77 R100/7
The small hole that Jeramy describes is the breather for the float bowl. It has to be there so gas can enter from the tank and exit into the engine. It breathes. There is also a small tube sticking up from the base of the bowl. The top sits above nominal fuel level but if the bowl over fills it will flow out the tube. Called the overflow.