7/84 k100rs fuel sender tank

Been working on fuel tank, pristine insides. As noted by dealer mechanic on an old service receipt, "there's no fuel sender in tank?" Is this common on early K bikes? There's no hole. No indentation for a hole. Zip, zero, nada, nein, nyet.

The early K100 bikes had a fuel-strip type sending unit and they were notoriously not accurate. They often showed low fuel when full or half full, and sometimes failed to show low fuel when the tank was empty.

Set your trip meter and fuel accordingly. Range is probably 160 miles or so. Get a gas can with fuel to take along and test it to sputtering.

So that's it. Thought I had a collectible.

Look at the left forward end of the tank. From inside there should be a black tube about 3-4 inches long, from outside there should be a large black plastic nut by the electrical connections. That is the original fuel level indicating system. It operated two lights, 7L and 4L. Most eliminated the 7L indicator by removing the bulb. My '85's unit still works with the original sending unit in there. It was explained to me a long time ago that BMW used temperature sensitive diodes to measure fuel level. This type of system cannot be used with a fuel gauge. If the sending unit is not there, there will be a 1" (?) hole where it goes.

Frank

The 84/85 used the black tube near the front of the tank. You can see it by the screw knob in from of gas tank on Left side. The 86+ used a rod and ball float to measure fuel level. The sensor is located in the back of tank. the two do not interchange. I would find another dealer if they don't know that.

Thanx all for responses, cleared up another item about which I didn't know much. Only bought this one because it was very clean, had a lot of service receipts and I needed something to do. Stuck camera into that nook and saw the plastic tube which probably still contains the strips. Got a new pump and carrier, looks like I'm done in here. Am working on shaving down an old corbin now, and polishing up a knarly original muffler.