6 gal tank but only putting 5.5 gal when run empty

[blown alcohol]

What would the problem be?
I usually never let it get too low, but I'm going on a 2 week trip out west in Aug.
I remember last year riding the bike home from work I thought I could make it across town to grab gas/groceries in one stop.
It started cutting out. I would turn it off and coast, then crank and run to coast till I got it mile to the gas station.

How much of this 6 gal tank should be usable? Bike is a 2013 cvo ultra

[roadkingdresser]

2019 r-king i've put 5.8 gal in it a couple times without running out. i'd be careful out west depending what roads you're on gas can be spread out a lot. in montana a lot of exits say no services. easier to get it early than to run out.

[chaos901]

Don't know what could be your problem.  On my 2010 Ultra I have put right at 6.0 gallons in and I was not quite empty yet.  Was checking something at the time and carrying a little gas should it have run out on me. 

   

[markymark]

Why run it so low ? You do realize that the fuel actually keeps the fuel pump cool.

[Hossamania]

Why run it so low ? You do realize that the fuel actually keeps the fuel pump cool.

Sometimes it happens. Especially when running where fuel is scarce.
And sometimes I just don't want to stop and don't have to pee!

[PoorUB]

Why run it so low ? You do realize that the fuel actually keeps the fuel pump cool.

Old wives tail. The fuel running through the pump lubricates it and keeps it cool. Take one apart sometimes and you will understand. There is absolutely no issue running a tank low. Out , maybe, bit not low. Also, do you think they would manufacture a fuel pump that would fail when you run out of fuel? Some guys I know would be replacing fuel pumps like tires! I know I guy that ran out of gas twice on one trip!

And also, like Hoss said, sometimes fuel isn't available, or you miss one stop and the next is a stretch. It happens when you ride the western states.

I regularly run my motorcycle until they are low on fuel and in 200,000 miles never had a fuel pump fail.

Also, I have put 5.8 gallons in a few times in a 6 gallon tank.

[bobrk1]

Yeah  I  put  5.8 in ,I also  put  5.25 in a 5 gallon  tank  who knows  the  last  time  it was  calibrated .

[tomcat64]

Why run it so low ? You do realize that the fuel actually keeps the fuel pump cool.

Old wives tail. The fuel running through the pump lubricates it and keeps it cool. Take one apart sometimes and you will understand. There is absolutely no issue running a tank low. Out , maybe, bit not low. Also, do you think they would manufacture a fuel pump that would fail when you run out of fuel? Some guys I know would be replacing fuel pumps like tires! I know I guy that ran out of gas twice on one trip!

And also, like Hoss said, sometimes fuel isn't available, or you miss one stop and the next is a stretch. It happens when you ride the western states.

I regularly run my motorcycle until they are low on fuel and in 200,000 miles never had a fuel pump fail.

Also, I have put 5.8 gallons in a few times in a 6 gallon tank.

dang it, you beat me too it..

[smoserx1]

Wonder if the 6 gallon rating is based on the tank being vertical, like on a trike?

[blown alcohol]

I have talked to a few that have put more gas in than what I did (only 5.5 gal). I was out of gas on the 5.5 refill.
I will check it out before the trip.
I ordered the 61011-04A fuel filter o-ring, and the 75254-04A strainer (sock).
Probably not the problem, but if going in tank might as well change, the parts are cheap.

[PoorUB]

dang it, you beat me too it..

What's wrong? Did work get in the way of wasting time on HTT?

[blown alcohol]

While out riding today I fill up, and reserve has 318 miles till empty. That being off is not nearly as bad as running out of gas and only refilling with 5.5 gal.

The gas gauges have really been accurate doing these years of bikes. Older bikes NO.
What do you think needs to be changed out?

Did the motor build and tune affect the reserve mileage display countdown? I still average about 40-42 mpg.
If so, it doesn't explain only putting in 5.5gal when ran empty.

[PoorUB]

When you say you put in 5.5 gallons, have you run it out of gas, or are you just looking at the gas gauge?

The gas gauges are very conservative. I could go another 20 miles after everything said I should be walking, and still had gas. A couple times when my miles remaining were at zero and the gauge was way past empty I ran another twenty miles.

If you really want to know how far you can go, toss a gallon can of gas in the trunk and ride until you run out. Toss in the gallon and run to the closest gas station and fill up. Then you will have a better idea of how far you can go.

[kd]

Run it till it's just about empty.  Drain the tank at home. Refill it and you will know.

[Tail Ridr]

The tank itself is probably 6 gal without any entrapped air pockets and you have the displacement of the internals that will also take up some of that fluid space... half of a gallon, including an air pocket?  Does the pick up line actually suck the tank completely dry? 

Same issue on our big diesel trucks, tank tag actually states 150 gal capacity, but only xxx useable

[PoorUB]

Tail, why would his six gallon tank be different from everyone else's? I haven't heard of anyone else complain of the capacity on the HD gas tanks, so something tells me his method of measurement needs work.

[blown alcohol]

Bottom line--either the stores pump was off, or something is not letting pump get all the gas on bottom.
because, I coasted in on fumes bike would not run just seconds at a time. I only could put in 5.5 gallons.

One day I will put gas in trunk and run gas out, then fill tank. I may or may not do this before west coast trip. I am riding with friend that only has a 5gal tank.

[hattitude]

Bottom line--either the stores pump was off, or something is not letting pump get all the gas on bottom.
because, I coasted in on fumes bike would not run just seconds at a time. I only could put in 5.5 gallons.

One day I will put gas in trunk and run gas out, then fill tank. I may or may not do this before west coast trip. I am riding with friend that only has a 5gal tank.

Have you inspected or pulled the internals from the tank...?  Maybe you have an issue in your fuel pick up...? 

Could be something like a hole in the fuel line, just above the bottom of the tank, that keeps you from drawing that last .5 gal...??

[kd]

^^  This is a good point  ^^  If you are going off on a trip you may want to consider checking this out.  If this suggestion turns out to be on the mark, you could find yourself  stranded somewhere that you can't get what you need to fix it and ruining your trip experience.  One thing I have noticed over the years, when something is beginning to fail and I didn't pay attention to the early signs, I very often paid for it later (and not in a good way )

[Tail Ridr]

UB-My '14 Limited shows ~35-40 miles remaining when my low fuel warning comes on...I may be in the same boat as Blown, it usually only takes around 5.3 to 5.5 gallons to fill when the gauge shows empty, but have never run it 'til it sputters.  I've always thought that some day I would run it 'til it dies to know how far I really could go past what is considered empty. I recall back in the day of a manual tank valve having "run" and "reserve"...is there a built in "reserve" past what the fuel gauge does consider empty? But anyway, my wife would have to come rescue me with a measured 6 gal jug when I run out and see how much fits...only problem being, she's usually with me, so I haven't done this test yet.  I usually start my hunt for gas at a quarter of a tank, which would leave me with a presumed 1.5 gallons (maybe) but by the tank design, is it...? I may try and find out 

[blown alcohol]

Tail Ridr,

I bet you're good if you have put in 5.5g before. I coasted in a good ways, and then only put in 5.5.
I have parts that will be here in about 2 weeks. I don't want to open it up until I have parts in hand.

I was so shocked I ran out of gas. I wished I would have shook the bike to see if I could have heard any gas sloshing around in the tank.

[PoorUB]

Tail, both my 2010 and my 2016 when ran down to empty and zero miles remaining had well over 1/2 gallon left, probably closer to a 3/4 gallon. That was one gripe I had about the bikes. Why have a gas gauge that says empty when you have 40 miles to go? I know they probably build them that was to save the riders that push the limits of the fuel capacity.

My 2010 I even took the sending unit out of the tank and bent the float a bit to try get it more accurate.

My BMW is no better. It is advertised as a 6.6 gallon tank. I have run it to "empty" a few times and put in barely over 5 gallons!

[Hossamania]

These are all reasons why I use the guage as a reference,  but use the odometer for accuracy. And I try to not push it, fill at 3/4 empty. If out in the boonies, and you need gas, but no station known to be close, it really doesn't matter what your guage or odometer says, you either make it, or you don't. Keep track of your tank, and fill early when in unknown territory.

[jmorton10]

I know Harley gas gauges are never very accurate so years ago I started using the odometer as my gauge.

Interesting though is with my 07 RK I use one of those kuryakin led gauges that is combined with battery volt gauge in the left side gas tank cap. It displays green leds as it counts down. When fuel gets low it displays yellow & red leds & I found out last year that when that starts flashing I need to find a gas sttation ASAP lol !!

I had just left my house & my first stop was going to be a gas stop. I pulled out of my neighborhood & stopped at a red light & the bike stalled.  I was thinking that's odd it has never done that before. It restarted immediately but as soon as I got moving it started sputtering & I immediately realized I was going to be real lucky to make it to either of the stations near me lol. I made a right turn & headed to the one station that has a gradual down hill grade leading up to it.  I made it to that stretch of road just as the bike completely died & then coasted all the way down that stretch & straight up to a pump lol.

There is one guy who works at that station that is a real wiseass (I love the guy). He was out at the pumps BSing with a woman he knew. He commented that he had heard of changing the pipes to quiet down a bike that was too loud but he thought I had gone a little overboard when quieting mine down lol.

~John

[WhipLash96]

Fuel density plays a role in capacity. Pump gas is very inconsistent as far as its weight is concerned. I sell Racing fuel so I have to be cognasent of these things when customers are looking for answers about fuel.

[PoorUB]

These are all reasons why I use the guage as a reference,  but use the odometer for accuracy.

I don't know how one can just go by the odometer. With my Harleys I could be getting 30 MPG or close to 50 MPG depending on conditions. That is a range of 150 miles to 250 miles to empty. My BMW is even worse! Mid 30's to 60 MPG depending on conditions, or 225 to 400 miles. I ride strictly by the miles remaining readout and the gas gauge. I never worry about how far I have gone on the tank. Sure the gas gauge is inaccurate, but it errors to the conservative side. It may say empty, but there might be 40 miles left in it.

[Dan89flstc]

Fuel density plays a role in capacity. Pump gas is very inconsistent as far as its weight is concerned. I sell Racing fuel so I have to be cognasent of these things when customers are looking for answers about fuel.

Fuel density has nothing to do with the capacity of the tank.

Fuel dispensed at the pump is measured in volume, and tank capacity is measured in volume.

A 5 gallon bucket holds the same amount of fluid, whether it is water or lead...

[Ohio HD]

Fuel density plays a role in capacity. Pump gas is very inconsistent as far as its weight is concerned. I sell Racing fuel so I have to be cognasent of these things when customers are looking for answers about fuel.

Fuel density has nothing to do with the capacity of the tank.

Fuel dispensed at the pump is measured in volume, and tank capacity is measured in volume.

A 5 gallon bucket holds the same amount of fluid, whether it is water or lead...

[Appowner]

Just wondering but I'm assuming the 6 gal capacity came from the MOCO specs/advertising.  So just how did the MOCO come to that figure?  Anyone know?  Was it some convoluted math formula or actual, physical testing?  With or without the guts?  And did they leave an air gap or fill to the brim?  And could they have rounded the number up at all?

As the bike sits upright is the fuel pickup at the lowest point of the tank?  Just how much gas might be below the pickup or even in some other part of the tank that doesn't fully drain to where the pickup is?

And how much air gap did you leave in the top of the tank when you filled it?  I'll wager the MOCO filled it to the very top in their test.  Assuming they did such a test.

I wouldn't worry about a gas pump that says you put (and paid for) only 5.5 gal in a 6 gal tank.  If indeed you have a 6 gal tank and filled it completely then that's a half gal of free gas.  I'd be more concerned if the pump said I put 7 gal in a 6 gal tank.  That's a gal of gas I'm paying for but not getting.  But I'd be surprised to find a pump functioning normally that is that far off.  Especially at today's prices.

[smoserx1]

So just how did the MOCO come to that figure?  Anyone know?  Was it some convoluted math formula or actual, physical testing?

Long time ago I was reading a thread somewhere about center stands on baggers and one of the posters said on the center stand he could get about a half gallon more gas in like that.  Makes sense.  A lot of the tank capacity goes away when the liquid lever reaches that "arch" where the tank sits on the frame backbone and when that happens the level starts dropping faster than before at the same consumption rate, but there is even more to it.  When sitting on the side stand the surface level is actually true but since the tank is tilted will appear higher in the left side of the tank, and on my bike that is where the sending unit is.  My gauge will absolutely read higher when the bike is on the sidestand.  That is why I am thinking the capacity (however it is figured) is based on a  straight up tank.  I really doubt temperature expansion of fuel or pump inaccuracy is enough to make a noticeable difference.  But for instance a lowered bike with  the same sidestand (which now sits up straighter) could make a  difference you could discern.

[Yellowbird]

Before you ask, and NO I don't do this on the reg. I went on a outing with the boys. Low fuel light was on and I was
planning on stopping at my Shell gas station. Arrived at my house and realized I didn't stop at the Shell.

Anyway, next day road to back to Shell gas station which was 2 miles away and topped off the 6 gallon tank.

Again just to show everyone, and NO I don't run this low all the time.


YB

[Appowner]

I have a good 40 miles left or more than a gallon when my low light comes on.  Just saying.

[chaos901]

We just finished a trip out west and I had at least 1.4 gallons left when my fuel light came on. 

[kd]

I just noticed my 2011 touring owners manual states the fuel light comes on at 1 gallon (3.8 litres) remaining. Knowing your mileage can be very helpful.

[Ken R]

When you say you put in 5.5 gallons, have you run it out of gas, or are you just looking at the gas gauge?

The gas gauges are very conservative. I could go another 20 miles after everything said I should be walking, and still had gas. A couple times when my miles remaining were at zero and the gauge was way past empty I ran another twenty miles.

If you really want to know how far you can go, toss a gallon can of gas in the trunk and ride until you run out. Toss in the gallon and run to the closest gas station and fill up. Then you will have a better idea of how far you can go.

Mine is very conservative.  But I have a PowerVision on the bars all the time and can see to within a few 100dths of a gallon how much I've used.  It's uncannily accurate! 
Every gas stop on our 4,500 mile trip the last two weeks, within 1/10th of a gallon compared to the station pump.
When my gas gauge says I should be walking, I have only used 4.9 to 5.1 gallons (according to the PowerVision).

Try this:
Siphon the tank dry.  Then put exactly 3 gallons into the tank. 
Hop on and ride around the neighborhood.  (static testing is useless).  The gauge should settle down to show a half tank on the nose. 
That should be good enough. 

I'm convinced that the fuel pump/fuel level sensor assembly float arms get slightly bent when being installed at the factory.  It's really tough to get all that stuff through the hole and set right.
I've adjusted several motorcycles by bending the arm slightly to indicate more or less fuel.  Once adjusted, it stays adjusted.

Ken