BMW R850R Fuel Pump, Tank, Water in the Gas

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bmw r840r fuel pump assemblyMy problem was a couple of cups (approx. 200 cc) of water in my tank. This was probably from condensation. I guess the previous owner stored the bike outside during the winter. The water was not creating an obvious problem until one day I dropped the bike on the right side in a parking lot. All the water ran to the right side of the tank, and the bike started having a misfire. It was confusing until I pulled off the tank.

Before getting started mark which fuel line goes to which connector on the bike. The outlet from the pump is the lowest connector. The injector is the middle, and the return to the tank is the top.

Also note the arrow on the filter. This is the direction of fuel flow.

Here is the pump/filter assembly out of the tank.
fuel and water in the bmw r850r tank.Here's the inside of the tank with the fuel pump removed. The inside of the tank is painted red. Notice the brownish puddle of water in the lower half of the opening. I'm using a turkey baster to suck out the fuel/water. The tip of the baster is right at the interface between the water and fuel.

The water was somewhat rusty, but I think the rust in the tank was minor, and once the water was out, the rust should stop. I keep the bike in the garage, and I use Chevron Techron fuel treatment every few tanks to remove any water.

All the water and fuel must be removed. I wiped the inside of the tank clean and dry as much as possible.
fuel and waterThat's fuel and water. The upper (lighter) colored liquid is fuel (oil floats on water). The water is in the bottom, and it's rusty brown.
fuel water mixtureThat's a turkey baster full of nasty water/gasoline. Notice the gloves. I'm putting the mixture into a clear container so I can see how bad it looks. The container is a paint mixing cup, which is cheap, has measure marks on it, and is resistant to all kinds of organic solvents.
fuel and waterThis is about the full extent of the water. Some probably drained out when I was draining the tank before removing it. I decanted the fuel that was initially drained out of the tank, and used the good part in the lawnmower (I don't have photos of the first step where I drained a couple of gallons of fuel out of the tank). What remained after decanting, and this went into my "bad fuel" can for disposal. Our local landfill has a hazardous waste collection day.