Fuel gauge interpretation / MPG

[Ken]

I'm puzzled by the fuel gauge. I've re-read the Owner's Manual on the gauge, and done some searching in here but haven't found anything that really explains what I'm seeing.

I've put 1200 miles on my ST since I bought her a month ago. Recently I've started paying more attention to gas consumption, miles per tank, and the readout for average miles per gallon.

Normally when I get down to one bar, it flashes that I have about 50 miles to go. This morning on my way to the gym, as soon as it started flashing, it said I had 30 miles to go. I finally stopped for fuel when it said I had 10 miles left to go. I had put exactly 300 miles on the bike since the previous fill-up. I filled up, right to the bottom of the neck as I always do, and it took 6.1 gallons.

Am I misinterpreting the gauge? If fuel capacity is 7.6 gallons, there was ~1.5 gallons left. And yet I had put 300 miles on her - 50 miles to the gallon (no complaints there). It's almost as if the gauge does not count the fuel in reserve.

Any insight is appreciated. Either I'm being really thick, or the sensor is not accurate.

[Ken]

Thanks for taking the time to explain this. It is much more clear now. I was perplexed on why it was telling me I had 10 miles left to go, and yet still had 1.5 gallons left in the tank. It makes sense now.

As an aside, I am thrilled with the mileage I am getting with this bike (40 MPG commuting, 50 MPG touring). Not only is it more fun to drive than my sedan, it makes trips to the pump a bit less annoying.

[Rick]

Man thanks a lot! I'm here (a new member) specifically because of the confusion on the gauge. Now what about the inaccurate speedo reading? You seem like the guy to ask!

Rick

[crazykz]

Thanks for taking the time to explain this. It is much more clear now. I was perplexed on why it was telling me I had 10 miles left to go, and yet still had 1.5 gallons left in the tank. It makes sense now.

As an aside, I am thrilled with the mileage I am getting with this bike (40 MPG commuting, 50 MPG touring). Not only is it more fun to drive than my sedan, it makes trips to the pump a bit less annoying.

How anyone gets 50MPG on the highway is beyond me but I know others have done it. For me it's 42MPG on the highway and abour 40MPG commuting.

Anyway, wanted to thank Leo for the right up. I've spent some time on this subject also as I had the thermistor in the lower tank go out and cause my guage to read no lower than 2 bars. I ran out of gas 3 times trying to figure out what the h*ll was wrong with it.

Basically the useable fuel in the tank is going to be about 7.2-7.4 gallons. At least this is all I could put in 2 different times when it was empty. I do my calculations for distance on 7.0 gallons to be conservative. This morning I road about 20 miles after I started flashing on one bar and put in 6.573 gallons. So I probably could have gone another 40 miles but I doubt it. Trying to get a consistent reading from the guage (forget about the fuel estimator) is just about impossible even under almost the same conditions from tank to tank. I commute the same way everyday with the same load and basically the same conditions and find that it still varies on how far I can go after I hit one bar. Basically you end up filling up once you hit one bar which is fine but for distance rides I need to stretch that out.

That's why I can't believe the amount of difference people are getting in fuel mileage. It amazes me.

279.8 miles/6.573 Gallons = 42.57MPG, but that assumes that the trip meter is accurate and I'm betting it's off by a few ticks.

Anyway I could go on for hours.

YMMV,
Curt

[Ken]

Riding style certainly has something to do with it, but I'm not sure to what extent. I don't ride aggressively, mostly upshifting at 3K. I'm certain from riding other bikes and being involved with other boards over the years that mileage varies depending on many variables including weight carried, riding style, wind resistance (size of shield and other deflectors), and fuel quality (I personally get slightly better mileage with name brand fuel (Mobil, Sunoco, Exxon, etc.) than I do with convenient store gas.

[CrashTestDanny]

How anyone gets 50MPG on the highway is beyond me but I know others have done it. For me it's 42MPG on the highway and abour 40MPG commuting.


I saw 52 MPG on one tank of gas. During that week I was forcing myself to drive at the speed limit and take a long time to get there. Since then I had been running 46 MPG (these numbers are calculated based on mileage and fill-up amounts, not what's indicated on the guage which is typically 3-4 MPG less). That was until my last oil change. At the last oil change I switched to HP4 (synthetic) 20w-50 and my mileage has decreased to about 40 MPG.

[Killtimer]

How anyone gets 50MPG on the highway is beyond me but I know others have done it.

I average over 50 mpg hwy/city and have done so on both my '13's. My secret........ Use Imperial gallons. :D :D

[Bones]

I always fill up using the center stand, always record miles and number of gallons purchased (for business reasons...I write for a living, sometimes about motorcycling).

Some statistics for 16,000 miles of riding:

Average 43.6 miles per US gallon
Rarely below 42 or above 45
Lowest individual tank: 39.1
Highest individual tank: 49.0

Results have much to do with terrain (mountains and twisties are good for fun, bad for MPG), weather (cold and wet reduce MPG), and distance (better MPG on long trips, even if all back roads).

No significant change in MPG based on tire brand (I've had stock BT020's, Z6's, and currently Pilot Roads).

I get better MPG on long trips. I use a Givi top case on long trips...don't know if there's a correlation.

I always look over the windshield.

I ride without a pillion 95% of the time.

Anyone who wants an Excel spreadsheet that calculates MPG, etc., (created by someone else) can email me through my profile. I'll send it to you... .xls files cannot be posted on this board.

[Hewhois]

How high or low you have your windshield set can make a big difference in your MPG.

[rom]

on my 6,000 mile trip this year I Averaged 50.12 mpg.
The best I've got is 55.23

My tank has 1.5 gallons left when the 'blinking' starts.
:03biker:

[crazykz]

Mine has 1 gallon of useable fuel when it starts blinking.

Curt

[racer1735]

:mad: I'm feeling left out reading all these 40+ mpg reports....I've had my '04 for just over 4 weeks now and consistently get between 37-39 mpg average per tank. The majority of the running is country backroads with some interstate thrown in, very little 'in-town' riding. I took a 200 mile trip to Chicago last weekend and averaged 38 mpg. I weigh 190 lb., still have the stock air filter, stock fuel regulator, stock exhaust, etc. and run 42 psi in both front and rear tires. I'm not overly heavy-handed on the throttle, but do like to put the miles behind me (generally 10 mph over the posted limit). Where is my 'economy'????

[Kennedy]

Canadian gallons I have done 59.5 MPG (calculated) on the hi way riding two up. Usually around 42 city. I have filled up immediatly when the fuel bar starts to flash and there is usually 7 ltrs in the tank at that point.

[Bones]

:mad: I'm feeling left out reading all these 40+ mpg reports....
I suggest you compute actual fuel economy rather than rely on the computer. No vehicle I've had with a trip computer ever gets it right.

Fill you tank (I always put mine on the center stand). Record the odometer reading. Set one of your trip computers to zero. Ride until your low fuel light blinks and fill up again. Record the odometer reading and volume of fuel to refill. Divide miles ridden by gallons needed to fill up and you have miles per gallon on that tank. Do this over a period of several weeks then take the mean and you'll have a better idea of your actual fuel consuption. I write down where and when I buy fuel to help me determine if I get better mileage depending on terrain, weather, load, enthusiasm, etc.

For what it's worth, I always calculate this information (long-time habit for business miles...my Dad and Granddad did the same). It's useful...a sudden drop in fuel economy not accounted for by riding conditions typically spells a problem somewhere. [That's never happened on any of my Hondas :) ]

[EdsST]

For me it all depends on how I ride. If I'm doing 85 on the interstate I get around 42-43 mpg, if I'm taking it easy on back roads I get 47-48 mpg. So I can see that there can be big differences in what people get depending on how they ride. What I manually compute is always higher than what the computer tells me.

[Kempo-STer]

:mad: I'm feeling left out reading all these 40+ mpg reports....I've had my '04 for just over 4 weeks now and consistently get between 37-39 mpg average per tank. The majority of the running is country backroads with some interstate thrown in, very little 'in-town' riding. I took a 200 mile trip to Chicago last weekend and averaged 38 mpg. I weigh 190 lb., still have the stock air filter, stock fuel regulator, stock exhaust, etc. and run 42 psi in both front and rear tires. I'm not overly heavy-handed on the throttle, but do like to put the miles behind me (generally 10 mph over the posted limit). Where is my 'economy'????


Racer..
Don't know how many miles are on the bike you have..
But the first couple of months with my brand new 05. I had the same questions..everyone on the board was taking consistent 40s for MPG..
My readout was always mid to high 30s..
Don't know what it is but as the oil changes (I also change the Final drive oil at every oil change) have gone by, my mileage readout has gone up to basically join the rest of the crown with concern to MPG readout...

I now most of the time readout in the mid 40s, once in awhile high 30's and sometimes 50's..I usually have had it set to the 'immediate' (recalcs every 20 seconds) readout mode but seeing this thread again, I think next tank of gas I will reset the AVG MPG and pay attention to that for wahile..

[Carl_T]

I don't ride aggressively, mostly up-shifting at 3K Holy Hat Hanna! That explains it for me, I guess my 6300-7800 RPM shifts might have something to do with it then :o: I guess I'll just pay the piper on that one.

My gas mileage experience is very close to Bone's.

A note on the gauge, when mine reads average fuel consumption of 39.9 the actual fuel consumption calculation turns out to be more like 45.5 mpg or so. It's kind of like the speedometer, they have it set to ultra conservative guesstimation.

[wjbertrand]

Man thanks a lot! I'm here (a new member) specifically because of the confusion on the gauge. Now what about the inaccurate speedo reading? You seem like the guy to ask!

Rick

Rick check out this thread:

http://www.st-owners.com/forums/showthread.php?t=4103&highlight=speedo+healer

[bill kohn]

I have had two extended trips, one for 3400 miles and one for 1400 miles. I purchased new my ST1300 in May. On my trips except for one tankful lduring each trip I averaged about 50 mpg based on mileage and fuel at the station-not based on a computer. One tankfull each trip resulted in mileage of 43 or 45 mpg, felt to be due to the station putting reg. gas in the premium storage tanks (is this a possibility?) We cruised between 65 and 95 mpg in the Northwestern states and I even saw 130 indicated when I averaged 50+. No trunk, but both saddlebags and one up only. The windscreen 1/2 way up. I am amazed at the mileage. I had a 1500 wing and could never get better than 42mpg if I went faster than 55mph. Perhaps I'm super gentle on the throttle. Perhaps my tire pressure (42 f and r) is too high. But no complaints her. Cheshire

[nurseBob]

I have had two extended trips, one for 3400 miles and one for 1400 miles. I purchased new my ST1300 in May. On my trips except for one tankful lduring each trip I averaged about 50 mpg based on mileage and fuel at the station-not based on a computer. One tankfull each trip resulted in mileage of 43 or 45 mpg, felt to be due to the station putting reg. gas in the premium storage tanks (is this a possibility?) We cruised between 65 and 95 mpg in the Northwestern states and I even saw 130 indicated when I averaged 50+. No trunk, but both saddlebags and one up only. The windscreen 1/2 way up. I am amazed at the mileage. I had a 1500 wing and could never get better than 42mpg if I went faster than 55mph. Perhaps I'm super gentle on the throttle. Perhaps my tire pressure (42 f and r) is too high. But no complaints her. Cheshire
Cheshire,
I find my milage varies between 42 - 46 during my weekly commutes. I've hit 50 on the longer trips where I tend to cruise around 75. While my commute cruising speed's similar, it also has a cross town ride in San Francisco, which really impacts milage. Also, like you, I've found the bike to be very sensitive to windshield position and tire pressure.

Bob

[elg476]

Hmmm.... How do you know when you're over-filling the tank?
I always put it on the centerstand and fill the tank 'til the gas
comes up to the metal bar that crosses the fuel opening (looks
like a silver strap).

Am I over-filling the tank? And what is an "evap canister," and
where is it?

Thanks, and sorry for the dumb questions.

-- Ed

> e) You can get more fuel in the tank (and more range)
> by filling on the center stand. Personally I don't
> because the extra range is not that critical to me and
> I prefer to avoid overfilling and permanently damaging
> the evap canistor ($$$). The fuel pump/sensor and
> sender assemblies take up some volume; 7.3 gallons
> is the most I've seen reported to fill an empty tank.

[mcyrus]

Thanks for the link to the STOC thread. I ran out last week for the first time while the guage indicated i still had 22 miles left. 24,000 miles on an '04, so far. On board computer indicates 42.8 mpg. 48 miles one way commuting. Passing as much as possible.

[Darth Vader]

Wow, this thread has been going on for some time. One thing that may help out with gas mileage is using the octane recommended by Honda. If they say to use 87 then go with it. Running a higher octane than needed may actually do harm. At least, more harm than good.