Author Topic: Fuel Level Send(FLS) - Adjust Low Fuel Level Indicator  (Read 834 times)

Offline frankenduck

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Fuel Level Send(FLS) - Adjust Low Fuel Level Indicator
« on: March 08, 2023, 04:59:53 PM »


From the factory the low fuel indicator is supposed to come on when you have 5 liters (1.3 gal) of fuel left. However sometimes that is not the case. Fortunately, motobricker rbm figured out how to adjust this.

It is binary in its operation: an open circuit when you have lots of fuel and a closed circuit when fuel gets low.

Below are some new pics of where the adjustment gear is.

Unfortunately, I'm 99.99% sure that you need to take the FLS out of the tank in order to do this.

First determine if you have an early or late FLS. The part number is stamped on the body of the FLS.
Early (Up to Jan/93): 62161459565
Late (From Jan/93): 62162305558

Here's where the gears that you need to turn are:





I assume that it is pretty sensitive since the arc of the FLS arm's travel is pretty small so you probably only need to move it a few degrees.

Note that in order to keep the low fuel lamp from flashing on and off as gas sloshes around in the tank there is some dampening/delay circuitry built into the instrument cluster. Therefore it takes a while (10-15 seconds?) for the lamp to come on.

Side note: If you're ever riding on fumes and the motor starts to stumble as you run out fuel then you can get a little farther if you lean the bike to the left while riding. This works because the fuel pump is on the left side of the tank. (This technique saved me a lot of pushing one day when it got me the last 1/2 mile that I needed to go to make it to a gas station.)

IMPORTANT: In order make this thread more useful we need some DATA. So if you do adjust the low fuel gear then please report your "before" fuel level, which way you turned the gear wheel , how many teeth you turned it (or fractions therefof) and the "after" fuel level. Before and after pics would be ideal.

Putting a mark with a Sharpie pen on the little gear wheel before you take pics would be great for showing how much you rotated it.
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Offline Chaos

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Re: Fuel Level Send(FLS) - Adjust Low Fuel Level Indicator
« Reply #1 on: March 08, 2023, 05:51:38 PM »
Another low fuel tidbit, at least on mine, if I think it's getting low I can test it by accelerating hard, if it's really low fuel sloshes to the back of the tank away from the pickup and the engine stumbles.
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1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

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