Fuel pump and filter

[TIV]

Since I had a new Mahle fuel filter I decided to take a look at the one in my bike. As can be seen on the picture below it has never been changed since new. Itīs dated 27th of September 1989. My bike is 1990 model.

Since I was in there I decided to check the fuel pump, fuel lines e.t.c. It looks like it wood be a good idea to change the fuel lines, the big filter under the pump has holes in it and the rubber could look better.

As can be seen on the picture below, there is a threaded hole in the bottom of the pump with some kind of an offset stud inside. I wonder if this is as it should be? Kind of looks like something should be screwed in there?  :dunno2:

It would be great if someone out there has a new or used pump handy, and could take a look at it for me and compare it to the picture. See if something is missing, or if it is as it should be.

[Inge K.]

As can be seen on the picture below, there is a threaded hole in the bottom of the pump with some kind of an offset stud inside. I wonder if this is as it should be?

That is the pressure relief valve (opens at 4.5 bar)....all things looks to be normal.

[TIV]

Great, thanks Inge. Everything was working fine, I was just curious. I will renew the fuel lines, filter and the rubber sleeve, it has started to crack and is a rather loose fit on the pump to.  :2thumbup:

By the way. It would be interesting to know what is the average lifetime on the fuel pumps and pressure regulators on these bikes?

[Big_B]

Great, thanks Inge. Everything was working fine, I was just curious. I will renew the fuel lines, filter and the rubber sleeve, it has started to crack and is a rather loose fit on the pump to.  :2thumbup:

By the way. It would be interesting to know what is the average lifetime on the fuel pumps and pressure regulators on these bikes?

My '93 K1100rs had 56,000 on it when the pump started getting very loud. Changed the original filter in '12, but shortly after the oringinal pump failed. Running a Ford mustang pump with no issues now.

[johnny]

i been using the napa 3032 filter... i change it approx every 10 thousand miles... $40 bucks per a 100 thousand miles seems like a good investment for this motobricker to keep the fuel pump happy...

j o

[Inge K.]

By the way. It would be interesting to know what is the average lifetime on the fuel pumps and pressure regulators on these bikes?

My oldest K (-86./+200K km)...still got the genuine pump and FPR......
....but it also haven't been a drop of ethanol inside the tank.

Inge K.

[TIV]

My oldest K (-86./+200K km)...still got the genuine pump and FPR........but it also haven't been a drop of ethanol inside the tank.

Hey Inge, what is this about ethanol? Has ethanol been used on these bikes? Never on mine for sure.

[frankenduck]

Ethanol does not, per se, cause problems with K bikes. I've run tons and tons of it through all of the K bikes I've had and never had any fuel system problems.  There is a BMW technical service bulletin (SB-00-021-07) which states that use of ethanol of up to 10% is fine in K bikes.

However, since ethanol tends to attract water, it has a rather limited shelf life compared to pure gasoline. It's not the ethanol that degrades the fuel system, it is the water that it attracts. This is why K bikes that sit for several years tend to have the vibration dampener reduced to goo, rusted and frozen fuel pumps or corroded gas tank leaks at the welds at the bottom seams of the tank.

Moral of the story: Ride your K bike often and don't worry about it.

[WayneDW]

My oldest K (-86./+200K km)...still got the genuine pump and FPR........but it also haven't been a drop of ethanol inside the tank.

Hey Inge, what is this about ethanol? Has ethanol been used on these bikes? Never on mine for sure.

In the U.S. it is getting very difficult to find gasoline without 10% ethanol mixed in.  The politicians do that to help out the millionaire farmers and to stick it to the arabs.  Many don't agree with the policy.  (danger, this might now turn into an ethanol thread)