Inaccurate Fuel Gauge

[travelinman]

I understand that motorcycle fuel gauges shouldn't be trusted too much but mine won't read full after a complete fill up unless I brake hard. Almost immediately I lose another bar after just a few miles. Is there a fix ??

Thanks

[BFish]

I understand that motorcycle fuel gauges shouldn't be trusted too much but mine won't read full after a complete fill up unless I brake hard. Almost immediately I lose another bar after just a few miles. Is there a fix ??

Thanks

 

same thing happens on mine periodically...overall i believe the guage to be accurate. one bar at the full level does not seem to be indicative, to me, of inaccurate readings down to the light coming on.

[Bernie]

I believe the Bar readout and the yellow low fuel light are operated by two different switches. But the best method is to reset the tripmeter after each fillup and to learn what you normal range is.

[Boffin]

I understand that motorcycle fuel gauges shouldn't be trusted too much but mine won't read full after a complete fill up unless I brake hard. Almost immediately I lose another bar after just a few miles. Is there a fix ??

Thanks

 

This is quite common, I read in a magazine once that a dealer can recalibrate it but I have not checked that out - the top of the guage is not important to me.

 

The low fuel light is independant of the fuel guage, it is driven by the float on the fuel-pump plate. The fuel guage is driven by a tubular float assembly. This means you have a double-check on low fuel levels. My low-fuel light comes on at 1 bar, and I have about 1 US gallon left at that point.

 

Cya, Andy

[madness522]

Mine does the same thing. If I put in on center stand it usually holds enough to get 10-15 miles from the station before the I loose the top bar.

 

Whats more important....How much room you have left in the tank or how much gas you got until it quits running?

[John Dickens]

Mine does it too.

 

Downhill or stationary it reads OK then drops 2-3 bars when moving. All connections are OK so I presume it's either the sender unit or the display. Neither are cheap or easy fixes so I live with it and watch the mileage.

 

Yes the fuel gauge and the fuel warning light have different sender units.

 

The gauge is driven by a 'dip tube' type sensor on the right of the tank. You can see the mounting plate when you take off the right side body panel. BUT the wiring is inside the tank so you also have to remove the fuel pump plate to disconnect it.

 

The light is tripped by the float unit attached to the fuel pump plate on the inner right hand side of the tank.

[Paul Mihalka]

I understand that motorcycle fuel gauges shouldn't be trusted too much but mine won't read full after a complete fill up unless I brake hard. Almost immediately I lose another bar after just a few miles. Is there a fix ??

Thanks

Simple explanation: The fuel gauge was designed for the R1100RT and was not changed for the R1150RT. They both have the same gas tanks. The R1100RT had a short filler neck and the capacity was 7.2 gallons to the bottom of the neck. The R1150RT has a longer/deeper filler neck and the capacity is 6.6 gallons. So in the R1150RT with a full tank it is still short about half a gallon compared to the R1100RT and the top bar disappears very quickly from the gauge.

[SageRider]

If the top bar doesn't appear at all, or it appears for a much shorter duration than it did when the bike was new, there may be some added resistance in the sender unit circuit. In my case, cleaning the connector contacts took care of the problem. If I recall correctly, this connector is the one near the throttle cable junction box on the right side of the bike. (If I do not recall correctly, then follow the electrical cable from the fuel pump/ dual sender unit access panel to the connector.)

[Rob L]

Simple explanation: The fuel gauge was designed for the R1100RT and was not changed for the R1150RT. They both have the same gas tanks. The R1100RT had a short filler neck and the capacity was 7.2 gallons to the bottom of the neck. The R1150RT has a longer/deeper filler neck and the capacity is 6.6 gallons. So in the R1150RT with a full tank it is still short about half a gallon compared to the R1100RT and the top bar disappears very quickly from the gauge.

Paul is right about the longer neck. One solution is to drill acouple of small holes at the top of the filler neck to allow you to fill the tank completely. This will give you more range and and more miles before the gauge begins to drop. The down side to this is you may find a puddle of gas under your bike if you fill it up and then don't ride to lower the fuel level. The fuel expands enough to send raw gas to your carbon canister and can end up on the floor. I removed the canister and have experienced the puddle under the bike from over filling the tank and not riding enough to lower the fuel level. Now I only top off when I am going to put some miles on before parking.

If you choose to drill the holes, BE CAREFUL!!

Remove the neck and then drill it! Gasoline is volatile and introducing an electric drill and heat from a bit can be a source of ignition.

[Paul Mihalka]

I would not drill the holes in the neck as long as the charcoal canister is in place. If heating up the gas pushes raw gas out of the tank, it would go straight into the canister, which is a no-no. Forf any mod like this, remove the canister first.

[travelinman]

Thanks all, now it doesn't bother me !

[Reddog99]

Simple explanation: The fuel gauge was designed for the R1100RT and was not changed for the R1150RT. They both have the same gas tanks. The R1100RT had a short filler neck and the capacity was 7.2 gallons to the bottom of the neck. The R1150RT has a longer/deeper filler neck and the capacity is 6.6 gallons. So in the R1150RT with a full tank it is still short about half a gallon compared to the R1100RT and the top bar disappears very quickly from the gauge

The problem being referenced here seems to appear after the bike has aged some. My 1150 gas gage started acting up after about 50,000 miles. AND, I have an R1100RT filler neck installed. So the simple explaination doesn't hold water...

 

Pat

[SageRider]

If the top bar doesn't appear at all, or it appears for a much shorter duration than it did when the bike was new, there may be some added resistance in the sender unit circuit. In my case, cleaning the connector contacts took care of the problem. If I recall correctly, this connector is the one near the throttle cable junction box on the right side of the bike. (If I do not recall correctly, then follow the electrical cable from the fuel pump/ dual sender unit access panel to the connector.)

Maybe I need to state this a little stronger...

My bike when new showed the top bar for about 50-60 miles on a full tank. Over time it deteriorated until I rarely if ever saw the top bar at all on the same level full tank.

Cleaning the sending unit / fuel pump connector contacts completely eliminated the problem and restored gauge function to like new. I used plastic safe contact cleaner with a nylon brush to clean the male pins and multiple wet connections to clean the female pins.

Worked like a charm!.

[FlyingJoe]

there may be some added resistance in the sender unit circuit. In my case, cleaning the connector contacts took care of the problem.

 

This makes sense. I have the same problem on an R1100RS after 40k, top bar never shows, has slowly deteroriated over time. I will try cleaning the connectors.

[Haynes]

My RT never reads full and only ever shows 9 bars. My GS shows full for over 100km of riding after a fill.

I've learnt to just live with it.

[ShovelStrokeEd]

The only part of the fuel gauge of any importance at all is the bottom. The low fuel light takes over to really warn you. Get in the habit of resetting your trip meter at every fill up. You soon learn when it's time to get gas as well as have an easy estimate of fuel remaining.

 

Wouldn't it be nice if BMW provided two trip meters like Honda has been doing for about 6 years at least.

[Paul Mihalka]

Wouldn't it be nice if BMW provided two trip meters like Honda has been doing for about 6 years at least.

I don't have the exact specs as I'm at home and not at the dealership, but most if not all new generation (R1200x, K1200x) BMWs have two trip meters.

[Bob Palin]

The only part of the fuel gauge of any importance at all is the bottom. The low fuel light takes over to really warn you. Get in the habit of resetting your trip meter at every fill up. You soon learn when it's time to get gas as well as have an easy estimate of fuel remaining.

My guage has become more and more pessimistic at the empty end of the scale too which is a bit annoying, the trip meter is fine but the gas mileage is variable enough to want the extra hint from the light. At least it is pessimistic rather than optimistic, otherwise I'd be walking right now.