Question Fuel Economy Concerns

[fatearther]

I'm a new rider with ~2700 miles on my 24' NC750x DCT. My experience is limited to this bike, but it's always seemed perfectly fine. I only commute with my bike on a rural Florida highway, but I am getting only 49-51 mpg.

My ride is ~ 25 miles round trip on a 65 mph florida rural highway with only 4 stop lights with little to no traffic. I'm always in standard mode and never exceed 75 mph, usually ride at 65-70 mph. My tires (dunlop OEMs) are always at 36-42 psi, replacing these with Road 5s next week. I have no luggage, stock windscreen, givi hand guards, and crash bars with no additional accessories. But there's always a whole lot of human on my bike.

I'm 6'3" and 320 lbs, so it's always made sense to me that my fuel economy would be significantly worse than average. I'd just like some confirmation that I'm not overlooking something and my fuel economy makes sense given that I'm basically riding 2UP by myself. Anyone else my size and getting similar hwy fuel economy?

 

[milesprwr]

Sounds roughly right. For myself, I'm 5'11" and 180 lbs with gear. I've got a madstad windshield, R-Gaza crash bars, and a Givi V47 top box. When I'm going 75-80 mph on the freeway I'm getting 50 mpg. Worse if there's a headwind.

 

[670cc]

Speed and wind resistance put you at a disadvantage on fuel economy. High accelleration doesn’t help either. The NC is a weird bike in that it’s economy can range from 50 to 90 mpg, all depending on how it’s ridden.

 

[Rydinon]

Sounds a bit low to me, but you are a bit under double my weight in riding gear. Question. How do you calculate your mpg? From where I sit, the only way to do it is to ride the bike for a hundred or two miles, preferably on an interstate that is more or less straight and compare the mileage shown on the odo with a gps. I said an interstate that is more or less straight (as opposed to what we all like with lots of curves) because the gps calculates the distance as a series of straight line measurements. Once you know the odo error, monitor gasoline usage for a couple or three tankfuls. Fill it up to the same point in the neck and preferably use the same pump. Then do the math, correcting for any odo error. You will be within 10% due to gasoline pumps inefficiency and filling errors.

The mpg shown on the data computer on the bike does not correct for tire wear, odo errors or anything else that might influence the fuel consumption.

 

[fatearther]

Sounds a bit low to me, but you are a bit under double my weight in riding gear. Question. How do you calculate your mpg? From where I sit, the only way to do it is to ride the bike for a hundred or two miles, preferably on an interstate that is more or less straight and compare the mileage shown on the odo with a gps. I said an interstate that is more or less straight (as opposed to what we all like with lots of curves) because the gps calculates the distance as a series of straight line measurements. Once you know the odo error, monitor gasoline usage for a couple or three tankfuls. Fill it up to the same point in the neck and preferably use the same pump. Then do the math, correcting for any odo error. You will be within 10% due to gasoline pumps inefficiency and filling errors.

The mpg shown on the data computer on the bike does not correct for tire wear, odo errors or anything else that might influence the fuel consumption.

I had not considered odometer error before. That probably explains why my mpg is finally consistently above 50 now that my tires are worn....

I've calculated my mpg manually with the odometer. I'm not worried about a super accurate number. Just seeing other riders frequently reporting 60-70+ mpg had me wondering if I could do better. I am happy with the mpg I've been getting, but something closer to 60 sure would be nice.

 

[Rydinon]

IIRC, my Honda ST1300 had a 3% odo error and a 7% speedo error. The speedo was optimistic, I forget what the odo was. Discussions on that forum suggested that Honda did that sort of thing across several bike models (their cars were much closer to actual speed and distance). I have not yet checked my NC...I will this summer.

I confess to being skeptical of people quoting mileage numbers. I had a friend who told me he was getting high 30's in his pickup. He was a construction worker who always had his truck heavily loaded. No idea how he did his calculations. Everyone else I knew with similar trucks was getting mileage in the low teens.

 

[davidc83]

Sounds normal to me. Most of us dont ride 2 up (I dont) so as you stated, you have the weight of 2 up. I am 5'10" and 205 lbs and I get upper 50s riding 75mph, low 60s riding 70mph. You are pushing a lot of mass and at 6'3" you are a blocking sail in the wind.

 

[the Ferret]

Pushing a mid 50's horsepower 500-pound motorcycle beyond 60 mph requires rpms and lots of fuel. I'd guess the majority of us that get good gas mileage run mainly back roads at 45-55 mph between 2500 & 3500 rpms and weigh under 200#.

 

[CamaroEric]

I agree that it might be right. When I ride with my wife on longer trips on higher speed roads, we get about 55mpg (combined weight of 260lb plus some gear). When it's just me doing some city and some 55mph, I get 70-75 mpg. When I do 75-80mph solo, I also get 60-65mpg.

 

[EuropeRider]

I'm a new rider with ~2700 miles on my 24' NC750x DCT. My experience is limited to this bike, but it's always seemed perfectly fine. I only commute with my bike on a rural Florida highway, but I am getting only 49-51 mpg.

My ride is ~ 25 miles round trip on a 65 mph florida rural highway with only 4 stop lights with little to no traffic. I'm always in standard mode and never exceed 75 mph, usually ride at 65-70 mph. My tires (dunlop OEMs) are always at 36-42 psi, replacing these with Road 5s next week. I have no luggage, stock windscreen, givi hand guards, and crash bars with no additional accessories. But there's always a whole lot of human on my bike.

I'm 6'3" and 320 lbs, so it's always made sense to me that my fuel economy would be significantly worse than average. I'd just like some confirmation that I'm not overlooking something and my fuel economy makes sense given that I'm basically riding 2UP by myself. Anyone else my size and getting similar hwy fuel economy?

I stopped reading at 6.3 and 320 lbs. You need a BMW GS or RT my man! I am 6’ and already had to change the ergonomics of the 750 ….. you’re even taller. How can you ride comfortably!!??

 

[Deleted member 13708]

Pushing a mid 50's horsepower 500-pound motorcycle beyond 60 mph requires rpms and lots of fuel. I'd guess the majority of us that get good gas mileage run mainly back roads at 45-55 mph between 2500 & 3500 rpms and weigh under 200#.

Absolutely.

At 3,000 engine rpm in 6th gear you're lugging the mild tuned motor. That's inefficient.

Go out and do an economy run in 5th gear, don't use 6th.

New tires cause drag on the drivetrain unless they're rock hard. Case in point ...
Let's assume a new tire that's 36.05 inches tall compared a well worn tire that's 36 inches tall.
The traveled distance is roughly .10 inches different by GPS.
How many revolutions per gallon of fuel? 5,280 feet divided by 113 inches times miles traveled.
The total difference is remarkable on a low powered engine while lugging.

 

[670cc]

Absolutely.

At 3,000 engine rpm in 6th gear you're lugging the mild tuned motor. That's inefficient.

Go out and do an economy run in 5th gear, don't use 6th.

New tires cause drag on the drivetrain unless they're rock hard. Case in point ...
Let's assume a new tire that's 36.05 inches tall compared a well worn tire that's 36 inches tall.
The traveled distance is roughly .10 inches different by GPS.
How many revolutions per gallon of fuel? 5,280 feet divided by 113 inches times miles traveled.
The total difference is remarkable on a low powered engine while lugging.

What evidence or data supports your statement that 3000 RPM is lugging the NC engine and making it inefficient? I totally disagree with your claim.

My best ever NC mpg on a whole tank of gas was 94.5 mpg. The run was done at a near steady 45 mph in 6th gear, which is somewhere around 2250 RPM on a 670cc manual transmission model. I repeated nearly that on a second whole tank years later, run in similar conditions of 45 mph and 2250 RPM, and obtained 90 mpg over 300 miles. The best NC fuel economy comes at the highest gear, lowest RPM, lowest speed, at the smallest throttle opening.

To your suggestion about running in 5th gear rather than 6th, yes, I have done that and it negatively inpacts fuel mileage. The higher RPM creates greater friction losses in the engine

Honda marries the NC with their automatic transmission, and in D mode tries to run the RPM considerably lower than 3000, shifting to 6th gear at a point that brings the engine to around 2000 RPM. Along with that, the whole NC concept revolves around efficiency. Are Honda engineer’s ignorant on how to design an efficient engine/transmission combination?

Lastly, I don’t understand your point about tire revolutions per mile and tire revolutions per gallon of fuel. The moving motorcycle presents a load to the engine. At cruise speed, the operator will throttle appropriately to match engine power to the load in order to obtain a steady speed. How many times the wheel rotates may have some minor impact on total friction but I don’t see it being a significant factor. Scooters with fast rotating 12 inch wheels can get some pretty decent fuel economy, beating the NC in some examples.

 

[Deleted member 13708]

94.5 mpg on a NC is either science fiction or a downhill.
I've attempted and failed to pull 2,900 rpm on numerous uphill climbs.
I doubt that you weigh 320 lbs. Apples to apples if you please.

I regularly ride with other NC riders, 2 dct and 2 x. All are 750s.
The dash calculations vary wildly between bikes, I trust my GPS.

Tire circumference of the rear is the exact math required to authentically UNDERSTAND.

What you believe and what I know to be fact is 180 degrees in opposition.
My stated numbers are hypothetical, I won't do your specific math.

My OEM powered NC wakes-up in performance at 5,500 rpm. Yes 3,000 is lugging.
I can ride the bike at idle same as you. No thanks.

 

[fatearther]

94.5 mpg on a NC is either science fiction or a downhill.
I've attempted and failed to pull 2,900 rpm on numerous uphill climbs.
I doubt that you weigh 320 lbs. Apples to apples if you please.

I regularly ride with other NC riders, 2 dct and 2 x. All are 750s.
The dash calculations vary wildly between bikes, I trust my GPS.

Tire circumference of the rear is the exact math required to authentically UNDERSTAND.

What you believe and what I know to be fact is 180 degrees in opposition.
My stated numbers are hypothetical, I won't do your specific math.

My OEM powered NC wakes-up in performance at 5,500 rpm. Yes 3,000 is lugging.
I can ride the bike at idle same as you. No thanks.

There is no doubt that low RPM and high load yields the best fuel efficiency. The slower an engine turns, the less drag it experiences; and the more load on it, the more the throttle body has to open, which decreases the pneumatic drag on the engine. While power is not maximized, the drag on the engine is minimized, which in turn maximizes efficiency. Lugging is intentional by Honda to maximize the fuel economy. But please, don't take my word for it and follow my link below for more information.

Brake Specific Fuel Consumption (BSFC) – x-engineer.org

Tutorial on how to calculate and improve the brake specific fuel consumption (BSFC) of an internal combustion engine

x-engineer.org

 

[fatearther]

I stopped reading at 6.3 and 320 lbs. You need a BMW GS or RT my man! I am 6’ and already had to change the ergonomics of the 750 ….. you’re even taller. How can you ride comfortably!!??

My saving grace is my inseam is only 32" and my commute is only 20 minutes long. However, after upgrading my saddle to a Russel Day-Long Touring saddle, which is about an 1" taller, I am feeling much more comfortable. With the stock saddle, I was a little cramped and uncomfortable, but it was bearable. This is my first bike, so I'm still ignorant to how comfortable a bike can be. With my new saddle I would say my bike is now perfectly comfortable.

 

[670cc]

94.5 mpg on a NC is either science fiction or a downhill.

It saddens me that you may think I’m a liar, but I assure you it’s true. Here is the thread where I presented the story for the second 90(+) mpg run: https://www.nc700-forum.com/threads/90-miles-per-us-gallon-on-the-nc700x.21115/ The first (94.5) run story was in 2013, and I don’t think that thread is accessible anymore.

Another forum member that was here from nearly the beginning of the NC series, like me, has also demonstrated that high NC mileage around 90 (miles per US gallon) is entirely possible.

Enjoy your motorcycle.

 

[dduelin]

Lugging as a description is entirely subjective in these conversations which there have been many especially when the NC was new in the community of motorcycles. Some of us were here in 2012. The NC operates entirely in the low and mid range and it has no high rpm range. “Lugging” has the connotation of damaging or potentially being harmful to the engine but Honda designed the NC engine to run most efficiently at rpms many riders of normal mid/high range power motorcycles would consider lugging but it isn’t an rpm/load combination that harms this engine. Proof is in the DCT programming to shift into 6th at 37 mph under light throttle. (670cc models, I don’t have experience with 745cc models) The owners manual recommended shift point 5th to 6th repeats this for manual transmission models. Now if the rider opens the throttle to accelerate or climb a grade at 37 mph in 6th the DCT computer and the manual transmission rider's mechanical sympathy directs the transmission to downshift 1, 2, even 3 gears as necessary to prevent lugging but at steady state or light load the engine is perfectly happy operating at =/>2000 rpm in 6th gear and is most efficient as measured by mpg at these very low rpms. Honda wouldn’t have it doing so if it was harmful. Because of the 270 degree crankshaft’s uneven power delivery operating at low rpms or at somewhat higher rpms under higher load the engine pulses or vibrates in a manner that might alarm some riders into thinking something’s wrong but it is just the way this engine is. Tons and tons of threads in the past about this pulsing vibration but it’s normal. A rider can always operate it in a higher gear to smooth it out but it’s not hurting the motor to let it lope along - the DCT will downshift it as necessary to keep from lugging operation. If it wants to operate at any given rpm under 3000 then que sera sera.

Back in 2012-13 when I was exploring my own personal mpg bests with my 2012 manual transmission NC700X I laid a loop course of about 100 miles with no stop lights and no stop signs. I fueled up to the bottom of the anti-splash portion of the gas tank and returned to refuel up at the same pump. I rode a steady (as I could) 45 mph. Stock windscreen, no hand guards, small rider crouching. The only mpg worth quoting is corrected odometer distance divided by fuel burn and not just one tank. Track mileage and observe odometer error over time to average out variables. My best attempts have been in the low 90’s but I deleted the 2012 from my garage on the Fuelly app so I can’t produce the fuel logs from 30,000 miles of riding. I sold that manual for a 2015 DCT. The ‘15 DCT could not match the 2012 manual on my test loop and the best ever was 84.3 mpg. That bike had a 20” Madstad and Bark Buster hand guards which added frontal area. Attached pic is screenshot of my Fuelly app for the 2015 DCT. 94 mpg for a 670cc manual transmission is possible within my personal experience.

 

[the Ferret]

I have not been able to get into the 90 mpgs on my '21 DCT 750 but have on several occasions gotten into the 80's mpg out of a tank, but then I live in a hilly/curvy area of the country and am hardly ever going flat and straight. I agree Honda would not program their bikes to allow a damaging lugging situation, generally characterized by chugging or jerking, pinging, and an inability to accelerate smoothly. The DCT will automatically downshift long before lugging would occur. They perform well at very low rpms, and achieve high mpgs, because that is how they were designed and engineered.

The accessories we tend to put on them, larger windshields, hand guards, saddlebags, luggage racks, trunks, engine guards, etc all add weight and reduce the aerodynamic and fuel efficiency designed into the bikes. That and a lot of riders prefer not to ride their bikes in a fuel efficient manner.

 

[nissbird]

I am getting 70 mpg (US) varied riding, rider only 155lbs.

 

[ljurgens]

That and a lot of riders prefer not to ride their bikes in a fuel efficient manner.

I know I for one don't give fuel efficiency much though on a bike. I didn't buy it for that, I don't commute (WFH), but it is a nice thing to have if needed. My Trail125 gets all of 90 or better!
I remember guys griping about their Victory's not getting great gas mileage, but I had a Vision with a 6 gallon tank and it could generally outlast my bladder . I was getting in the 40's on that big bike, I'm getting in the 50's at least, maybe better, on my NC just from anecdotal evidence and I'm completely happy with that and ride the bike like I like to. For me thats usually in Sport mode but I'll probably program a user mode that is (2,2,2,3) so, mostly standard, just letting the DCT hang on to each gear slightly longer, which helps in the hills around me.