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I have a 2018 Tri Glide Anniversary edition with the 107cc. If I keep the rpm's between 2500-3000 which is the 65-70mph range I get around 32-33mpg. If I go over 3000 I to the 3100-3300 rpm range which is 72-77mph the fuel mileage drops into the 25-27mpg. I run none ethanol fuel either 91 or 93 octane but mostly 91.
Anyone else see thid kind of drop off in mpg? Any suggestions?
 

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Road Junkie
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Welcome to the forum. When you get a moment, go over to the New to the Community thread and do a detailed introduction so that we know how long you’ve been riding, your location, wrench skills, etc. It makes it easier to help you along the way.

As for fuel mileage, I see a marked reduction in fuel economy when I run above 75 mph. I’ve never ridden a trike, but your MPG is about 10 points lower than my two wheeled version.
 

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The more you twist the throttle , the lower your MPG will be.
It doesn't matter how many wheels you have.
Ethanol will give you 10% less mileage per tank. It is crappy fuel, avoid it if you can.
A HD Three wheeler is not very aerodynamic, you could try drafting other vehicles, but your reaction time better be fast if the other vehicle had to make a sudden stop.

I say ride at a safe distance and keep up with traffic no matter the speed and deal with the mileage one tank at a time, 150 miles per tank isn't bad for something so heavy.
 

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Just rode appxly 300 miles at appxly 80 mph on the interstate. I averaged 18 mpg. I was so upset. I had to make alot of gas stops. My trike is a 2017. Rode from Austin Texas to Mcallen Texas
 

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Interesting how much difference in speed at 3000. Im indicating 80 mph at 3000. Need different gearing allow for the weight get it moving and in power band.
 

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18 mpg at 80 mph isn't that bad! There's a hell of a a lot of wind drag. The drag goes up on the square with the speed.
As far asa I know, nobody buys any Harley with fuel economy in mind.
 

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When you buy an Harley it costs you big $$$ or in my case big £££ fuel economy is piss poor but if you live here in UK our gas prices equate to around $8 or 9 per gallon .
But yes I noticed the poor mileage per gallon according to the books a tank of fuel should give you approx 250 miles check your fuel gauge clock
 

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Considering the weight of a trike, depending on how much of a load you're carrying, your performance seems pretty reasonable for a stock motor. While the new M8 is a better performing motor, it's still not exactly a high performance motor. You're straining it pretty good to get that kind of speed. It's going to eat some fuel.

It's the nature of Harley motors to lose MPGs over 70 mph. At least for the Twin Cams, which I am familiar with. The difference for me running 60 versus 70 was 5-6 mpg when the bike was stock. I'm not surprised the M8 is similar.

Odd thing is that I build it into a 107 with about 40 percent more power, and it actually got the best fuel economy I've ever gotten with it on the C6 trip. I averaged 40 mpg and ran close to 80 on the interstate. The amount of twist in the wrist to get it to hold speed and pull hills is very noticeably less.
 

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Fat Guy on the Ultra
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I would say ride it the way you want, it's not about the miles per Gallon, but the Smile per Gallon...

again stay away form ethonal gas if you can, but due to the fact Harleys are like bricks, they do decrease mpg when going over 55. I can get around 45 mpg if i stay on a flat road around 55mph, but if I hit the interstate @ 80mpg I get around 25-28 mpg. and that is staying in 6th gear. on a Ultra classic. i honestly couldnt tell you my exact mpg. I just come to the conclusion if I am burning more gas then I want to, I just stop riding.... lol
 

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Wayward Son
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I would say ride it the way you want, it's not about the miles per Gallon, but the Smile per Gallon...
^THIS^
Never cared. Or worried about MPG`s.
Since my first Harley in 84. Took notice of my rough miles per tank.
Allowed for load, speed, heaviness of wrist to gauge the next gas stop. Never looked back.
As long as there was not a noticeable drop which may indicate a problem.....
I just rode. It`s why I bought it. :nod
 

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Viet Nam 69/70
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1 up on rides under 55mph 40+ mpg
2 up on rides under 55mph 40 give or take
2 up pulling trailer 55-65 35 +or- headwind drops it by 2-3 mpg
2 up pulling trailer 70-80 30-32 mpg
Anything more for speed or headwinds will drag it down to 28 mpg

The only reason I keep track is when the light comes on, or the mileage hits the 5gal usage, I know what I need to do. I have turned around not daring to push the limits out west or remote areas.
 

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I have never been overly concerned about mpg on my bike. But I did track it a bit when I had my '13 RGC, 103 with stage 1 and added cams to improve low & mid range torque. Numerous times I checked mileage on that '13 and generally got somewhere in the mid to high 30s, occasionally in the low 40s. Did I mention I LOVED to hear my Rinehart Tru Duals @ 5,000RPM?

The '16 RGU I got last September, 103 with stage 1 and FP3, has the infotainment center and I've used the GPS maybe 7-8 times for trips of usually an hour or more. Most of those times I knew how to get where I was going but I was just experimenting with the navigation. But after each "trip" I looked at the Trip Summary and, so far, my mileage has always been between 44-49 mpg. Amazing, at least to me.

Not long after I got the '16 last September it was due for the 10K service. My regular indy also checked my brakes and lots of other things for me and he said he also took out both spark plugs, said both of them were the perfect color and told me "Don't change nuthin".
 

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Keep on Ridin’
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A 650 Kawasaki gets great mileage.



But I’m never gonna find out how great.




Sent from my iPad using Tapatalk
 

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Yup milage definite varies with speed. My average is 40 (you can check out fuelly to see what other people get for vehicles. They have everything in there) but managed 50 on a tank once taking the slow back roads through New Mexico into Colorado. Even my 800cc Suzuki cruiser only did about 40mpg.

Another way to look at why is the definition of horsepower. 33000 pounds / feet /minute. Same load/distance at higher speed is literally more work. More work requires more effort.

Sent from my SM-G950U using Tapatalk
 

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91 FXLR
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There are some things you can do to a Fuel Injection Bike. Such as Performance Tuning, Air Intake, Performance Pipes. Maybe you can get a larger Throttle Body.

I take a lot of vacations. I have 2 Harley's, the Bike's are tuned for MPG and they are Identical in setup Carbs, Plugs, Air filters, Performance Pipes. Here at home I get 39.5 MPG running 72MPH. Last summer I took The 1999 Fatboy to Sturgis, Minot ND, Glacier National Park, Yellowstone West, Idaho Falls, Ontario Oregon, Redding CA, San Fran, CA, L.A. CA, Las Vegas NV, Denver, Albuquerque then home.

As soon as I got to Kansas City I started running in to 91 Octane NO Ethanol Gas which is Real Gas.

My Fatboy's MPG jumped to 57 MPG running 72MPH. My State like all States has Laws on the Books that define Motor Fuels. It says the MINIMUM OCTANE shall not be less than 82 Octane, so the Gas Co. are only going to put enough Octane to bring it up to 82 Octane because Octane is expensive. So the Numbers on the Pump mean nothing. All States have their own laws about Gas.

82 Octane is just enough to keep your auto or bike from Pining and having Run On. They do this to Rip you off and the Gov. makes a lot more Tax money. With Ethanol you lose 29% in MPG and Power so you have to spend more Money. Tennessee, and Florida do this. I went through Ohio one time and the Gas was Unbelievably Good.

Studies have been done, Ethanol is worse than None Ethanol Gas on the Environment. They say Trump is going to get rid of it, I hope He does...
 

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old scoot coot
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the main reason i did a decat stage one was to lessen operating temps a bit and lower fuel milage. my milage dropped from 1mpg to 1.5mpg. just right, running a little richer now that epa regs have been circumnavigated.:grin
 
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