Fuel gauge bars

[Ian]

With an absolutely full tank is eight bars the maximum?

 

Ian

[Boffin]

A full tank should, in theory, give you bars up to the top of the gauge (10?) - in prctice they are often a bit low. One cause is corrosion on the pins of the electrical connectors - both the tank connector below the rear-right-hand of the tank and the connector to the RID. Cleaning these with contact cleaner helps. On the 1150, the tank filler has a deeper insert which helps to make matters worse than on your 1100.

 

Other than that on US Spec bikes, sometimes the float tube in the front of the tank gets crushed due to blocked charcoal cannisters and prevents correct operation of the float. Very unlikely on non-US bikes as they only have a rubber vent pipe.

 

Andy

[AndyS]

With an absolutely full tank is eight bars the maximum?

 

Ian

With the filler neck mod I have mentioned in your'overflow tank' post - when my tank is TOTALLY brimmed I can then get all bars showing. However if you left the bike parked, expansion of the petrol in the tank would cause it to come out of an overflow.

So, in truth, if you fill your tank to the bottom of the filler neck, you are normally 1 bar down.

Andy

[Mr. Frank]

I'm with Andy. One bar down is normal for me.

[4wheeldog]

Mine is somewhat sensative to fuel quality......Non ethanol fuel shows a full tank longer. I did not see 10 bars for a couple of years (Only 8, most of the time), until I flushed the brakes last, and cleaned the contacts in the connection others have mentioned. I now get a full reading on every fillup, takes anywhere from 10 to 30 miles for the firstAfter you clean the contacts, use some dielectric grease in the connecter to make your cleaning last longer. Good Luck!

[breyfogle]

Two bars down is the best my RID has ever done.

[Charles Elms]

On the center stand mine always goes to 10 when full. After about 25 to 30 miles it drops to 9. Lower bars drop faster than top ones.

[Selden]

On the center stand mine always goes to 10 when full. After about 25 to 30 miles it drops to 9. Lower bars drop faster than top ones.

That's an interesting observation; I hadn't thought about it on the RT until you pointed it out. A few weeks ago, I heard an interview with an automotive engineer who confirmed what I have always suspected: gas gauges are deliberately designed to be inaccurate. On every car I can remember over the past 20 years, the needle stays on full for a loooong time after a fill, and the second half tank seems to go faster than the first half. If I remember correctly, the engineer explained that the first quirk makes people feel better about their gas mileage, while the second is to provide a greater cushion against running dry.

[outpost22]

On the center stand mine always goes to 10 when full. After about 25 to 30 miles it drops to 9. Lower bars drop faster than top ones.

On every car I can remember over the past 20 years, the needle stays on full for a loooong time after a fill, and the second half tank seems to go faster than the first half. If I remember correctly, the engineer explained that the first quirk makes people feel better about their gas mileage, while the second is to provide a greater cushion against running dry.

 

Sounds 'bout right. It seems like a lot of gas tanks are wedge shaped so when they're full, they have the larger part of the wedge fuller longer...if that makes sense. As it tapers down in size, the needle drops faster.

 

I know in one of our rigs the darn thing reads 1/8th tank with about 35% still left in the tank. In the boat it reads 1/8 BELOW empty when it has 10 gallons of the 34 gallon tank still left! Since I use about 5-10 gallons/year in the boat, the needle always is below "E". Leaving ethanol gas in it for long periods is a bad idea, even though it's stabilized with fuel treatment. I just carry a 5 gallon can with me when the boat is in operation.

I wish the darn things were accurate.

[szurszewski]

My RT always showed full bars at fill up and usually for about 30 miles thereafter....until the gauge tube was crushed last summer - now it shows just over half bars when full until about a hundred miles in when it drops to three bars where it then remains.

 

As to the inaccurate fuel gauges in other vehicles, our previous Silverado with a 22 gallon tank would stay about full for 70 or so miles, creep towards a half and arrive there at about 200 miles...and then plummet to E in the next hundred miles (though we did squeeze 360 miles out of a tank looking for gas in the middle of the night in rural Ontario). Our current Volvo, which has the gauge marked in gallons instead of fractions, is pretty much right on - except that there seem to really be about four gallons left when it says there are only two - haven't fully "tested" it yet by running it empty though.

[Haynes]

My R1150RT shows the full 10 bars and appears to read accurately. I also have an R1150GS that never reads more than 9 bars.

[AndyS]

Its pretty hard to make gauging accurate when your petrol tank is the shape that the RT is.

The gauging mechanism only reaches so high up into the tank and if you fill above that point (like I do whenI go for the overfill), then it will read full for a long time until it has burnt the fuel down to a point where the gauging becomes active.

Then the next problem is the relative area of the tank changes, initially quickly, then it slows down where the tank is largest, then it will quickly change when it gets to the lower region.

Unless there was a complicated fuel computer that could compensate for the change of shape of the tank, then you are asking a lot.

I just think I am lucky having a gauge. I just used to have a petrol tap with a reserve position.

Now I can worry about it a lot longer while I watch the bars descend.

Andy

[DD 430]

Its pretty hard to make gauging accurate when your petrol tank is the shape that the RT is.

The gauging mechanism only reaches so high up into the tank and if you fill above that point (like I do whenI go for the overfill), then it will read full for a long time until it has burnt the fuel down to a point where the gauging becomes active.

Then the next problem is the relative area of the tank changes, initially quickly, then it slows down where the tank is largest, then it will quickly change when it gets to the lower region.

Unless there was a complicated fuel computer that could compensate for the change of shape of the tank, then you are asking a lot.

I just think I am lucky having a gauge. I just used to have a petrol tap with a reserve position.

Now I can worry about it a lot longer while I watch the bars descend.

Andy

 

I'm with you: it used to be a hassle, not to say dangerous, reaching down while under way to rotate the petcock on the tank when the bike started to sputter. My first VW had the same sort of arrangement - when the car started to die (always in traffic)you had to kick the reserve lever over with your right foot to keep the bug running - then the car had another 30 or-so miles left in it.

 

I'll take an inaccurate gauge (and a little common sense)over no gauge at all.

[Charles Elms]

My first VW had the same sort of arrangement - when the car started to die (always in traffic)you had to kick the reserve lever over with your right foot to keep the bug running - then the car had another 30 or-so miles left in it.

 

Ahh..Memories. You could move the reserve lever half way (never in traffic, usually in a isolated place) and it would cut off the gas totally. Good way to 'run out of gas' with a date and not have to walk to get gas later...

[Ian]

Andy,

 

I believe I was the first, around 2002, to report that the connector above the RH injector was another cause of low fuel gauge reading. Ever since I cleaned it thoroughly with contact cleaner the gauge has never risen above the eight bars even if filled to the brim.

 

I recall someone posting that there is an other connector in series somewhere closer to the gauge and this might be providing the extra resistance to lower the m.v. to the gauge.

 

thanks,

 

Ian

 

[azccj]

On my 04 RT, when I fill it up while on the side stand, the RID shows 10 bars for about 10 miles then drops to 9 bars.

[Ian]

Thanks everyone for your bar heights

 

Ian

[Quinn]

On my 04 RT, when I fill it up while on the side stand, the RID shows 10 bars for about 10 miles then drops to 9 bars.

 

My '04 RT also. I usually fill up around 200 miles on the trip odometer with two or three bars left by adding around five gallons (US).

 

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[Dan M]

I almost always fill on the center stand. 10 bars shows for at least 20 miles. Low fuel light comes on around 230-240 miles.

[GregsARed]

One cause is corrosion on the pins of the electrical connectors - both the tank connector below the rear-right-hand of the tank and the connector to the RID. Cleaning these with contact cleaner helps. Andy

 

Well that might explain things or at least if gives me a fix.

 

Upon filling the tank mine would always read 10 bars. Then shortly after reading something from P.G. abut the effects of ethanol on the tank float, mine would only go to 9 bars. I blamed the ethanol and by this time there had been a lot of 10% ethanol in the tank. I'd rather not use it, but sometimes it's unavoidable.

 

Well while on the road I needed some ASAP clutch related work done and since then it was back to 10 bars. Had no idea why but was happy. That only lasted a couple months then back to 9.

 

Because all the parts for the previous mentioned fix weren't immediatly available, I scheduled some follow up work over winter. After that it's again going to up to 10. Whatever?

 

Mystery solved?:

With both maitenance repairs they needed to disconnect/connect that plug. That action alone probably made for a better electrical connection. Something else that needs to be cleaned.