Fuel computer accuracy

[the Ferret]

The 14 models have a trip computer which tells ( in two modes A& B ) mileage, gas used, average fuel mileage, and amt of gas left. I am continually amazed by the accuracy of this little computer, I mean being an old guy, I have to wonder how it measures the gas I use? Is it by weight? Or does it actually measure the fuel as it's fed thru the 4 throttle bodies? Or is there some other magical thing only young people would understand? Because it amazes me.

At any rate on last nights ride I was down to two bars and passing a station with a fairly good price on gas so I stopped and topped it off. Same procedure as every time, bike on the side stand, filling from downhill side with my left hand as I peer into the neck of the tank, fill until gas comes up into the neck and shut it off. I turned around and hung up the pump handle and the pump said I used 2.5 gals. Close cap, put key back in ignition, put tank bag back on, collect my receipt, fire it up and reach down to reset B mode which I use for the amount of miles on the tank ( A mode is for amount of miles driven daily as I record this figure in my log ). Anyhow B mode says I had driven 137.5 miles, push the button again and it said I had used 2.5 gallons ( exact same amount of gas I had just put back into the tank), push it again and it says I averaged 55 mpg. Same results I get when I plug the numbers into the calculator in my phone. Push the button again until miles on B mode pops up, and push and hold until it zeros, then push it back until I get to odometer. Ready to ride again.

I mean I can remember when we used to see how much gas we had left by opening the gas cap, rocking the bike back and forth between our thighs and listening for the volume of slosh we heard in the tank. Back when the bike would start sputtering and you'd reach down and turn it to reserve, Then when it quit altogether, you'd lay the bike down on it's left side to get the gas trapped on the right side of the tunnel over to the left petcock side. Then stand it back up and fire it up and ride another couple of miles, hopefully finding a gas station before you ran completely out.

Now your bike accurately keeps track of every drop in the tank. Like I said, these computers are simply amazing.

 

[davidantoniocostarica_imp]

It's amazing this system Ferret!
In my Shadow 600 the marker it's the power loss, and in this moment change your mode to reserve tank , and search the near fuel station
Sorry for my english translate style

 

[Django]

It's not the computer, the import thing is, that the sensors, e.g. to measure current volume of fuel, current speed and covered distance have become much more accurate. The computer then just adds numbers.

 

[DJS_imp]

It's not the computer, the import thing is, that the sensors, e.g. to measure current volume of fuel, current speed and covered distance have become much more accurate. The computer then just adds numbers.

regarding the fuel.....
is there a sensor to measure the fuel in the tank that feeds the computer or does it keep track of the fuel usage from the fuel pump?

 

[BestStandard_imp]

Here's how they work in cars: "The fuel economy gauge makes a calculation by counting the number and duration of pulses made by the fuel injectors as they squirt gasoline into the combustion chambers of the engine. The onboard computer system divides the distance the car travels by this estimated fuel consumption". and also "Honda uses additional inputs to calculate trip mpg. We look at the fuel-consumed data that comes from the engine-control computer, but we also track the float sensor measuring the fuel level in the tank".

 

[ride4now_imp]

It is pretty amazing.... mine has always matched what the pump says too!

 

[White Dog_imp]

I have the 2014 Standard. My "B" button seems to be inoperable. Can someone tell me for sure? The Owners Manual does not differentiale the standard vs. the DLX that I can tell.

 

[the Ferret]

I thought the 2014 std gauges were same as 2014 DLX only with black faces. It should cycle odometer (total miles on bike), A distance traveled, A gas used, A mpg ave, A fuel left in tank... B distance traveled etc each time you press the left button. Hold button down on distance traveled to zero either A mode or B mode.

Look in your owners manual and it should show that. In the meantime another 14 std owner should chime in

 

[xNE0x_imp]

It does all that, and mine also shows instant fuel economy.

 

[the Ferret]

I haven't figured out what that instant fuel economy number is, but it always seems high, like in the high 60's

 

[Rocky_imp]

As always ferret, you come up with some very interesting stuff

 

[Cormanus]

In a car, the instant fuel economy number is likely to be the amount of fuel you are using in real time. It goes up and down alarmingly depending on what you're doing. Accelerating, it is high. Slowing it reads zero and cruising, it's the sort of reasonable number you want to see.

But I've no idea if it's the same on the bike and I can't find a 2014 owner's manual on line anywhere.

 

[mininsx_imp]

They must have improved them because on my '08 Concours 14 and my 2010 VW GTI they're both never correct.

 

[Hittheroad_imp]

I just did 368 miles yesterday and the computer says 8.7 gallons used, 41.7 MPG. But my calculator says 42.3. This is the worst mileage I've ever had on my 14. But I was also going 75-80 MPH most of the time. The laws of Induced drag coefficient was my enemy!

 

[the Ferret]

Yea 80 mph really sucks the gas, but in the right circumstance can be totally worth it lol

 

[Hittheroad_imp]

I did find out a few things though.. I need a wind screen!

 

[Xyzzy_imp]

So far with six tanks my mileage computer has been within a few MPG. The other day, however, I purposely tried to get the best mileage I could on a ride. There was no wind and I stayed at 50-55MPH, just puttering around the farms near my house. The mileage computer reported 58MPG but my actual was 67.9MPG!

I am very careful with calculating mileage. I use the same pump and I park the bike so the sidestand rests on a little metal circle next to the pump. I fill the tank to where the gas just touches the lower lip of the filler neck. I never get the full six bars showing on the fuel gauge. It is always five.

I know all of that sounds tedious but I play it like a game. There are times I like to rip around like a whirling dervish and there are times I like to meander around and get lost. Fortunately where I live there is very rarely any traffic so I can ride at my own speed.

I run no-ethanol 87 octane gas. At 50-55MPH the bike is turning 2,250-2,500RPM. Even with hills and stuff the bike is very smooth and never lugs. I shift right before 3,000RPM and I try to keep the bike above 2,000RPM at all times. I was told once that 2,000RPM was the minimum speed for good oil circulation in the upper end of the engine. I don't know if that is true but it works for me.

My fuel stats: http://www.fuelly.com/motorcycle/honda/cb1100/2014/xyzzy/363319

 

[Stichill]

It's not the computer, the import thing is, that the sensors, e.g. to measure current volume of fuel, current speed and covered distance have become much more accurate. The computer then just adds numbers.

+1

 

[Xyzzy_imp]

I accidentally had to push the range on my CB today. The reserve counter counted down to zero and then it displayed a dash, and I still pushed on. In the end, I went 205.4 miles and used 3.35 gallons of gas for an average of 61.3 miles per gallon. The bike computer told me that I had used 3.4 gallons so that seems very accurate. The service manual tells me the 2014 "standard" fuel tank is 3.86 gallons. I don't think I could have pushed it much further because I think the fuel pump is submerged in the tank and needs fuel to cool it. (I might be wrong on that.)

My ride today was a mix of stop-and-go traffic, 70MPH slabbing and 50-60MPH back roads. I am very satisfied with the fuel economy that I am getting. I notice that the bike needs 10-15 minutes to warm up before it starts getting really good economy as displayed by the instant fuel economy readout. I typically get 65MPG at 50MPH, 60MPG at 55MPH, 55MPG at 60MPH, 50MPG at 65MPH and 45MPG at 70MPH. (At 105MPH I get a steady 22MPG.)

 

[the Ferret]

Sounds about right..only I have NO idea about mileage at 105 mph lol

At the rally on the Cheohala and BRP I was running 45-50 mph and averaging about 63 mpg.