Archive of BMW Motorrad Club Cape (2006 - 2019)

My 2001 1150GS with 205000 km on the clock stalled while riding one day, and would not start again.  The engine was cranking but it just would not fire.  I knew it was the fuel pump because I could not hear the pump prime when I turned on the ignition.

Some quick research to discover what replacing the pump would involve turned up this gem:

It highlighted the key parts of the process involved in removing the pump and filter from inside the tank.

Looking for replacement parts revealed this:

http://www.beemerboneyard.com/16141341231rk.html (a complete filter, pump, gaskets and fuel-line quick-connects for about $150 from the USA).

Some searches on Wild Dogs revealed a list of equivalent substitutes for the pump and filter - to whit:

1. Empty the tank

Just my luck to have filled the tank the day before the failure.  I tried siphoning fuel from the filler cap at the top, but my hose was too thick to go in  properly.

Instead, I loosened the tank, unplugged the electical connector, and removed the fuel line pipe from its connection to the pressure regulator.  I blocked the end of the pipe.

The other fuel pipe (the one above the fuel connection), is the fuel return line and when you disconnect it the petrol runs out of the tank.  I allowed it to pour into a canister (but not before getting myself completely covered in petrol.

Later, after I had removed the pump unit, I siphoned the remaining fuel with a fish-tank pipe. 

2. Remove the fuel pump and filter unit

I followed the instructions in the video.  Thankfully the breather lines were attached with cable ties and it was easy to cut them loose.  I attached some long cable ties to the breather lines and tied them to the outside of the tank so that they did not fall back in.

Breather pipes secured

You need to be careful, as the fuel guage mechanism is exposed and quite flimsy.

The fuel pump and filter unit removed from the tank

From the date on the filter I see that it was changed in 2012 - so the cause of the pump failure was probably not due to a clogged filter.  I suspect it was provoked by running dry during the Wild Coast trip.

The fuel hose clamps used by BMW are single-use clamps that are crimped with end-cutters.  They are designed to not cut into the hose and weaken it.  You pry them open with a screw-driver, though in the video the guys seemed to mangle them open with pliers.

If you use screw-type hose clamps, make sure they are designed to be used on fuel lines, and that they are stainless steel.

3. Replace the filter

After all this effort, you might as well just replace whatever you can.

4. Replace the fuel pump

I confirmed that my fuel pump was dead by connecting a 12V old bike battery to it.

The old and the new

I also confirmed that the new pump works in the same way (but only run it for a second - without fuel it will burn out if you run it for too long.)

End bracket holding the old pump in place: Notice the input sock that prevents bits getting into the pump and damaging it.

The old pump is firmly mounted with a short hose and a metal bracket.  After some difficulty I told myself the pump is broken anyway and jimmied the thing off with a screw-driver and loving force.

New vs Old

The new pump is smaller and shorter

The bracket must go

The new pump is smaller and shorter than the old one.  I cut off the bracket as it was in the way.  I was concerned that the shorted pump would not reach the fuel as well as the other one, so replaced the hose to the pump with a longer one so that the opening of the new pump was in the same place as the old one.

The new pump with lengthened hose and new filter

The new pump also had a different electrical connector, so I unsoldered the old wires and soldered on the new ones.  Be careful to connect positive and negative poles to the pump correctly.  On my bike, the old positive was green and the old negative was brown.  The new pump had a red (positive) and black (negative) wire.

New wires soldered where the old ones used to be

I replaced the old hose clamps with new ones that I had bought from Andrew.  You need an end-cutters (or side cutters), to clamp them shut.

5. Clean the tank

Might as well.  There were bits in the dregs of the fuel in the tank.  I took off the filler cap and roll-over valve.  Then I sprayed the tank inside and out with my equivalent of prepsol (MX Clean), and flushed it thoroughly with a garden hose.  The idea is to flush all muck out of the furthest corners of the tank.

Dry the tank as best you can and leave it in the sun and wind to dry out.  I finished it off with a bit of hair-dryer time.

Drying the tank

6. Quick-connects

Measure how much hose the quick-connects will replace, (mine are 5cm between the end of one hose to the start of the next).  Cut that much off the end of the two fuel lines that lead from the tank/pump into the bike behind the right pot.

How I used to seal the fuel hoses after fighting to get them off

Then, cut the remaining hose in two about 6cm from the new end, and insert the quick-connect there.  Make sure you face the quick-connect the opposite way on the second hose, so that you cannot accidentally connect the wrong hoses.

Quick connectors in place

The quick-connects on the bike

I spent quite some time confirming which hose went where.  This is the deal:

• the hose from the rear-most connection on the tank runs above the other one.  This is the "fuel return" line, and the one that gushes the most petrol from the tank when you disconnect it.  (Because it does not have the pump and filter to slow it down).  It is connected to the top-most pipe on the bike.
• the hose from the front-most connection on the tank runs underneath the other hose, and is connected to the bottom connection of the bike.  The middle connection on the bike goes to the fuel injector on the pot.

7. Assemble and test for leaks

When you re-insert the pump into the tank:

1. ensure the gasket (o-ring) is clean and in place,
2. don't forget to attach the two breather hoses,
3. DO NOT OVERTIGHTEN - it is easy to strip the lugs into the tank, or pull them out completely.  The recommended torque is 5Nm (i.e. 2kg of force 25cm from the nut).  And do them the way you tighten a tyre - do opposite ones in sequence.

To test, put about 5l of petrol in the tank and check for leaks.  Leave the tank on its side overnight to confirm the side plate is sealed.

8. Re-attach the tank and run the bike

With the new quick-connects, putting the tank back on was a pleasure.  After checking everything I tried to start the bike.  It would not run.

Then I remembered something Andy said about turning the ignition on and off a few times to let the fuel pump prime itself.  I did this quite a few times (at least 20), and cranked the engine between each.  Just when I thought I must have buggered something up, Mr.Badger took and ran like a sweet kitten.  Obviously it takes quite a bit to get the fuel flowing after such a dramatic cleanout.