Fuel economy is terrible!!

My UK bike.

When on long runs I will get an FCD display showing an average of 10 miles per litre. That is 45 miles per UK gallon.
Which is a tad over 37 miles per US gallon. So that given me a normal max tank range of 290 miles.

It can show 12 or even 15 miles per litre average, but our roads don't allow that to stay that high for very long.

On shorter runs or with lots of climbing or slow down / speed up sections it can drop to an average 9 miles per litre.
I don't use the 'instant' readout (ie updated every 15 seconds), as it can vary wildly. The average is the miles per litre which equals total mileage divided by amount of fuel - since the last trip set.

Mileage used is taken from the trip meter, and occasionally verified as being reasonable with the satnav track log. Track logs tend to be slightly shorter as they 'straight line' the route between adjacent points. The manual calculation is worked out from the amount of fuel it takes to fill the tank to the same level as it was when I last zeroed the trip.

The on board fuel 8-segment display varies between bikes. My current bike display is very different from my previous 1300. This one turn off the first segment within a few miles of filling up. My previous one did 45 miles before that happened.
My first 1300 would have a calculated 55 miles left when the last light started blinking. My current 1300 has a calculated 70 miles when it switched to 'miles remaining' when the first segement starts blinkign supposedly when 5 litres are left. That calcualtion is based on riding about 35 miles with a blinking light and working out how much fuel I had left when I refilled. Based on a 29 litre tank.

I do not ride many roads with long stretches so there is a lot if slowing, accelerating, climbing etc.

How does your speedo healer work if correcting the speedo doesn't affect the mileage? The info comes from the same place - The rotation of the wheels.

You say that your mileage and your trip meter and FCD display are accurate, but you don't say how you know that to be the case after fitting a speedo healer. I'm not being crtical here, but youve checked most things engine wise. Your brakes may be dragging, but I'd opt for the cheaper solution first and make sure the data that you are using is correct.

There is one very real possibility that you are throwing fuel away.

The water drainage tube that drains rainwater from around the filler neck may have rusted through and have a hole in it.
The tube starts with a hole on the left hand side of the fuel filler neck under the lockable cap. The metal tube passes through the inside of the tank, through the petrol, and emerges at the rear bottom of the tank as one of three pipe ends which you can see when you lift the tank. There it has a rubber tube attached which emerges at the left rear of the sump and spills its contents into the road.

That metal tube can get blocked by dust and sand that is part of every downpour. It traps water and never dries out. So it rusts. Eventually it rusts thriugh to the petrol, when two things happen. 1, you get rainwater in your fuel. 2 Your fuel slowly leaks out to the road and under your back tyre.

The rubber tube has a joint near the left hand mounting bolt of the seat sub frame, near your left knee. You can separate this and get gently blow compressed air back up the tube. This will clear any blockages, but might also reveal any air escaping into the fuel.

Its a long shot - but it has happened, and is probably something you may not have considered. Well worth eliminating.
 
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So pure highway/interstate pulling a trailer, no.mountains, the best mileage was 517 km’s.
Fill up took 26 litres
Flashing single digit bar on the dash
Audiovox cruise control on

Pure city stop and go driving, no highways 360 kms
Fill up took 22 litres.
2 bars still showing on the dash.
New thermostat this year

Before changing the thermostat this spring, 311 kms
Fill up 23 litres
Flashing single digit on the dash

Brake discs are all relatively equal temperatures on the city driving mileage.
I check the 3 brake discs regularly when arriving at work.
Rear one is alway a tad hotter the the 2 fronts.
I normally only use the brake lever and hardly ever use the pedal.
Estimating the brake disc temperatures
Fronts 40c
Rear 50c
 
Booster Plugs cause the bike to run in a constant rich mode, I think. If the bike has always done this, You may want to check to see if the bike has one.
 
The Dark Shadow said:
What is a booster plug...?
Click to expand...
A device that modifies fuel delivery in some way to alter the performance of the engine, preferably to deliver more power.
The Dark Shadow said:
My bike has a speedo fixer on it and the speedo reads pretty close to perfect.
Click to expand...
As a point of reference with the civilian model ST1300. Just about every civilian model ST1300 ever checked and reported about on this forum has a speedometer that reads in the range of 8% higher than actual speed as delivered from the factory. Most have an odometer that is quite accurate. The signal for the speedometer and odometer come from the same place. All commercially available speedometer correction devices alter that signal to correct the speedometer. Doing that throws the odometer off. It is not possible for this to happen unless the signal for the speedometer and odometer is being divided and the speedometer signal is then altered separately. I have never heard of a commercially available product that does that. I am skeptical of any claim that the speedometer and odometer are both accurate on an unmodified civilian model ST1300.

You have a 2014 ST1300, so it is a Police version is it not?
If so, none of the above applies because the Police version ST1300's have different speedometers and they are calibrated to be much more accurate from the factory. They also do not need any speedometer correction. If you do have a speedometer correction device such as a Speedo-Healer on a Police version ST1300, that would most likely make it less accurate.
I am not aware of anything on the Police version that would affect fuel efficiency. There are many people here who have the Police version who can report their MPG for comparison purposes.

Check to see if you have any fault codes stored in memory even if the FI light is not illuminating.
If all things such as the thermostat and other common maintenance items are in good shape as you contend, check the air intake tract for obstructions. It is well known that mice love to build nests in these motorcycles.
Confirm that no modifications have been done to it, such as performance modification devices such as a Bazazz box, booster plug, etc..
Check your brakes. They can be dragging and you don't notice it, especially the rear brake due to commonly experienced SMC problems. They may also drag only when warmed up so you don't notice anything when moving the motorcycle around manually so they appear to be fine.

For data purposes, the average fuel consumption that I have experienced over all of the miles that I have driven my civilian model 2009 ST1300 since new is 19.6 Km/L, 5.1 L/100 Km, 55.5 miles per imperial gallon, 46.2 miles per US gallon.
 
Andrew Shadow said:
ust about every civilian model ST1300 ever checked and reported about on this forum has a speedometer that reads in the range of 8% higher than actual speed
Click to expand...
I noted yesterday that my 2004's speedo reads about %5.3 higher than actual (gps) speed. This is pretty typical across my 4 honda's, which range in age from 1981 to 2012. So it's a long term characteristic of the civilian bikes anyway. And,,, btw,, remember that Honda was sued, way back,,, on the automotive side,,, for odometers that ran faster. The allegation then was that it was done intentionally to use up drivetrain warranty periods faster. So I never trust my bike's odometer. IBA only accepts gps and google maps mileage readings, as there is so much variation on bike odo's. I will test my 2012's odo this afternoon,,, and post the results. cheers,,, CAt'
 
I like to ride in Texas which has a lot of two lane highways with a 75 MPH speed limit. I typically ride five or ten over. My bike averages 44-45 MPG. It has NGK CR8EH-9 plugs. I’m not sure that makes any difference to the ECM though. I don’t think it does because the system probably isn’t sophisticated enough to tell the difference, I don’t think.

I know it’s unlikely but to me this looks like a dirty air filter. But if you changed it yourself you know it’s not. Could also be the fuel pressure regulator.
 
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Catmandu2 said:
I will test my 2012's odo this afternoon,,, and post the results. cheers,,, CAt'
Click to expand...
So I sync'd up the bike odo/tripometer with the gps,,, and went for a drive. The bike's meter hit 35km's at exactly the same time that the gps hit 34km's. So a 3% difference. Now I should point out that my rear tire of choice,,, is a 180/55zr17,,, not the oem size. And this tires diameter is slightly smaller than the stocker, so that affects the bikes distance measurement. But the tire size calculator shows that the smaller tire size could only account for about a %1 error. So given these differences,,, I will keep calculating my fuel mileage using pump and gps measures. cheers,, CAt'

170/60-R17 vs 180/55-R17 Tire Comparison - Tire Size Calculator | Tacoma World

180/55-R17 tires are 0.24 inches (6 mm) smaller in diameter than 170/60-R17 tires and the speedometer difference is 1.0%
www.tacomaworld.com www.tacomaworld.com
 
Catmandu2 said:
Now I should point out that my rear tire of choice,,, is a 180/55zr17,,, not the oem size. And this tires diameter is slightly smaller than the stocker, so that affects the bikes distance measurement. But the tire size calculator shows that the smaller tire size could only account for about a %1 error.
Click to expand...
Does that take into account the higher RPMs per MPH affecting fuel consumption?
 
Larry Fine said:
Does that take into account the higher RPMs per MPH affecting fuel consumption?
Click to expand...
The slightly smaller tire will increase my fuel consumption slightly, Larry, lol !! btw, During my afternoon ride,,, the bikes computer showed just over 21km/L on the long (4km) flat straights,,, at about 85kmph. But I know, from doing many properly measured mileage checks, that my overall consumption for this leisurely ride would have been about 17km/L. CAt'
 
Andrew Shadow said:
A device that modifies fuel delivery in some way to alter the performance of the engine, preferably to deliver more power.

As a point of reference with the civilian model ST1300. Just about every civilian model ST1300 ever checked and reported about on this forum has a speedometer that reads in the range of 8% higher than actual speed as delivered from the factory. Most have an odometer that is quite accurate. The signal for the speedometer and odometer come from the same place. All commercially available speedometer correction devices alter that signal to correct the speedometer. Doing that throws the odometer off. It is not possible for this to happen unless the signal for the speedometer and odometer is being divided and the speedometer signal is then altered separately. I have never heard of a commercially available product that does that. I am skeptical of any claim that the speedometer and odometer are both accurate on an unmodified civilian model ST1300.

You have a 2014 ST1300, so it is a Police version is it not?
If so, none of the above applies because the Police version ST1300's have different speedometers and they are calibrated to be much more accurate from the factory. They also do not need any speedometer correction. If you do have a speedometer correction device such as a Speedo-Healer on a Police version ST1300, that would most likely make it less accurate.
I am not aware of anything on the Police version that would affect fuel efficiency. There are many people here who have the Police version who can report their MPG for comparison purposes.

Check to see if you have any fault codes stored in memory even if the FI light is not illuminating.
If all things such as the thermostat and other common maintenance items are in good shape as you contend, check the air intake tract for obstructions. It is well known that mice love to build nests in these motorcycles.
Confirm that no modifications have been done to it, such as performance modification devices such as a Bazazz box, booster plug, etc..
Check your brakes. They can be dragging and you don't notice it, especially the rear brake due to commonly experienced SMC problems. They may also drag only when warmed up so you don't notice anything when moving the motorcycle around manually so they appear to be fine.

For data purposes, the average fuel consumption that I have experienced over all of the miles that I have driven my civilian model 2009 ST1300 since new is 19.6 Km/L, 5.1 L/100 Km, 55.5 miles per imperial gallon, 46.2 miles per US gallon.
Click to expand...
Damn... The BEST I can get it 15.6 km/l. A lot more trips to the fueling station...

I just read in a FB group one ST owner stating his thermostat was stuck open, even though there was no code showing nor did the 3 bar temp gauge display anything but normal behaviour. I'm going to have to consider this possibility further.

My 2014 is not a police version. They kept putting bikes out of the factory assembled from previously manufactured parts, as I am told. Mine has slightly different clutch and brake levers than my previous 2005 model.

No faults stored. (Had it checked last week.)

For whatever reason and I know not, my odometer reads close to bang on, and my speedo is bang on! (I know! Ask my local policeman... haha!!!)

Brakes have been checked and are "normal" and "regular". Although I want to check the double disks on the front again in case they are pulling a bit.

BTW, what state/province/country and what elevation are you in...? I read that altitude and heat make a big difference on mileage for this bike.
 
The Dark Shadow said:
BTW, what state/province/country and what elevation are you in...? I read that altitude and heat make a big difference on mileage for this bike.
Click to expand...
Montreal, Quebec. Mostly below 1,000 feet elevation locally and when I am not traveling.

Based on your responses, thermostat and/or dragging brakes.
 
The Dark Shadow said:
I just read in a FB group one ST owner stating his thermostat was stuck open, even though there was no code showing nor did the 3 bar temp gauge display anything but normal behaviour. I'm going to have to consider this possibility further.
Click to expand...
Most of the time a stuck t-stat will only show when you are in lower ambient temps as the radiator is free flowing and keeping the coolant at a lower temp. When it warms up a bit - outside temps - it will get to 3 bars and the fans will kick on keeping it at 3 bars and the fans keep up as the system is designed to work in those conditions.
 
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