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Gas Tank Removal

K75S Tank Removal

By: Bryan Lally
August 1995

(Editor’s Note: K100 info below)

I need to remove the gas tank to my ’92 K75S; however the Haynes manual is less than descriptive for this model. The manual describes two clips at the rear but where else is the thing attached? As far as the hoses go, do I need to watch for anything specific when removing or replacing the tank?

Loosen the hose clamp at the front of the fuel rail and remove the fuel line there. A little fuel will spill out (do it with a cold engine). I stuffed a rag underneath the rail to catch most of it.

Disconnect the electrical connection that comes off the back of the tank and weave the wire attached to the tank around so that it will be free when the back of the tank is raised.

Remove the two clips at the back of the tank that hold the tank down.

Raise the tank from the back, and remove the two lines near the right rear of the tank. Note which one goes where 🙂 One just pushes on, one has a hose clamp.

Remove the fourth line, way at the left front of the tank. This will be easier if someone else holds the tank up.

Pull the tank slightly back and up, and it is off. It is held on by the two rubber bumpers at the front, and the two clips at the back.

Reverse the steps to put it back on. Make sure you get the rubber bumpers in the right places. As to the two hoses at the back right of the tank, the front tank vent is for the air space in the tank – the heavy hose with the clamp, that leads to the crankcase through a one-way valve (the SHED system) goes on there. The skinny one that goes overboard is for the rear vent – that’s connected to the little hole under the gas cap. It drains the area around the gas cap. Don’t kink any of the lines, or pinch them between the tank and frame, or bad things will happen.

Gas Tank Removal – 1985 K100

By Don Eilenberger
November 1998

To actually remove the tank – you’ve gotta disconnect the two fuel lines (golf-T’s serve very nicely to plug the lines while it’s apart – which I’d recommend, and no, gas won’t leak out of the unplugged spigots on the tank – but I usually slip a few little pipe-caps over the ends. you want ones about 1/4″ ID). and you’ve got to disconnect the power line to the tank.

All of these are in the forward left side of the tank. and they are easiest accessed by removing the left lower panel on the fairing. which requires:

  • Remove left kneepad (two screws up in radio/glovebox, one screw down near your toe.
  • K100RT model only: Remove glovebox/or radio box – if you have a radio – see messages on removing it for K1100LT – it’s exactly the same. If not – remove glovebox, 4 screws.
  • Remove two (mebbe three?) screws that attach lower panel to upper panel – one is right under where the radio box goes.
  • Remove two screws from front – these are on the face of the panel surrounding the radiator.
  • At this point you’ll be able to see the two fuel lines and the electrical plug. Remove as above.
  • Remove 10 mm bolt from mounting at rear of tank.
  • VERY IMPORTANT – *remove side panels* – these snap into the tank at the front edge – and failure to remove them (BTDT) will break the inside mount for them (BTDT) if a past owner hasn’t already broken it. (I now have a sticker right next to the bolt that sez “SIDEPANELS??” – cause I have BTDT. more than once). Note that this design was changed with ’86 model year.
  • Lift tank up at rear, and slide backwards. it can then be lifted off.

The 4 way connector (why we’ve done this exercise) is prolly tie-wrapped to the frame. match connectors and start reassembly – which is reverse of disassembly.

OK – cautions – you do NOT want to get any dirt into the FI lines. the lines you’re disconnecting are AFTER the fuel-filter in the tank, and dirt getting into them will instantly go to an injector. This is not a good thing.

There may be a bit of fuel spilled – the fuel-rail will be under pressure if you’ve run the bike in the past hour or so – if you leave it sitting overnight – the pressure should have bled back into the tank. Be prepared with a nice throw-away rag when you loosen the first hose clamp. Alternatively, you can start the bike and unplug the electrical plug. When the fuel pressure goes to zero, the engine will stall.

Inspect your fuel lines – you have a 13-14 year old bike. If they look the least bit doubtful – replace them with FACTORY fuel lines. these are special lines meant to take FI pressure (which in the case of a failed pressure regulator could exceed 60PSI.)

That’s about it. it actually took longer to write it out then it should take you to remove the tank.

NOTE to others – the later (’86 and newer) tanks mount differently at the rear – two clips instead of the 10 mm bolt. Other than that the procedure is identical.

BTW – if you just had to slide the tankbag straps under the tank, you could loosen the rear bolt and slide it back a bit and lift up – the back of the tank can be lifted about 4″ without disconnecting the fuel-line hoses.

BTW2 – you MAY find that there are two small lines connected to nipples on the right rear side of the tank – these are the overflow line and the tank-vent line. Usually – these are not connected, but are directed at a little funnel arrangement that clips to the frame below them. IF you find they are still connected – I’d suggest getting the funnel thingie. it was a retrofit for early models.

BTW3 – there should be aluminum and fiberglass insulation attached to the bottom of the tank. This was also a retrofit to early models. if you don’t have it – it may still be an ‘open campaign’ and you might just get your dealer to install it for free via reimbursement from BMW.

Additional note:

By: Robert Carter
May 1999

I’ve found you also need to have a new set of grommets that the rear of tank sits on. Even if lubed up prior to pulling the tank up, they have a tendency to rip. 70 cents for two.

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