My MPG is fluctuating - why?

[TroutBum]

I have now filled my tank three of four times. The first was done by the dealer. Here are my MPGs:

85.3
95.4
75.2

Why the decline? I ride around town only. I ride around town and on the conservative side. I always fillup while on the center stand. I stop filling once the gas level reaches a cross tube at the bottom of the filler neck.

[jmazza]

Even if you are trying to fill up the exact same amount each time, it's pretty hard to actually do and with the small capacity of these tanks, a larger or smaller fillup make a pretty big difference in the calculations. That could certainly account for the different numbers.

[Edwub]

I have now filled my tank three of four times. The first was done by the dealer. Here are my MPGs:

85.3
95.4
75.2

Why the decline? I ride around town only. I ride around town and on the conservative side. I always fillup while on the center stand. I stop filling once the gas level reaches a cross tube at the bottom of the filler neck.

I've seen some variation in mine at times, though nothing tooooo crazy. But you need a good chunk of data points to be pretty confident in your overall average.

See my chart: (also viewable through the Fuelly link in my sig)



Mine is pretty clearly just over 50mpg in most of my riding situations. Any smaller variations are either error, or other conditions (temperature, weight, wind, etc). Some of them you can explain (that October/November bump was due to a long ride with the LA Scooter Group ). Some you can't (in Dec/Jan, it bobbled: user error? Did I overfill one tank, underfill the next, repeat? Or something else? I had trouble the first few months filling the Blur up, it took a bit to get the hang of it, and the data might reflect that). Even being off by .03 gallons will give you some decent variation of a few MPG. (Especially if you fill up more often, and I believe the Buddy tank is smaller than the Blur's).


Keep recording your data, and you get a good overall trend. Mine is West LA stop/go traffic on a 220 Blur, and I think most people viewing this thread would agree that Blitzen (in his typical riding conditions) gets just over 50mpg consistently. [That chart shows 32 fill ups.]

[pdxrita]

I don't know how big the tank on the Like is, but on a Buddy, with just a bit over a 1 gallon tank, that's pretty normal. With such a small amount of gas and a large amount of miles, a very small variation in the amount filled can cause what looks like wild fluctuations in MPG's. Just keep averaging it over time and you'll see it stabilize somewhere. That'll be the most accurate MPG figure.

[Capt_Don]

Your best readings will come in large chunks of time. If you fuel early it will tip the averages etc... over time it balances out.

[jprestonian]

I think most people viewing this thread would agree that Blitzen (in his typical riding conditions) gets just over 50mpg consistently. [That chart shows 32 fill ups.]

Holy crap! That seems awful for a Blur 220i!

My Kymco People 250 got better than that at all stages of its life. And it's not even fuel-injected!
.

[BootScootin'FireFighter]

Many different variables play a role. For example, I did a 303 mile trip last fall out to Charlottesville, back north on Skyline dr, then home from Front Royal in 1 day. The trip to Charlottesville was WOT, low elevation, slightly warm, and no vehicles to draft from. That leg of the trip indicated 82 MPG. After fueling up and hitting the Drive (higher elevations for the next 100 miles), I was about 1/2 to 3/4 throttle, colder air, lots of trees, no wind. That stretch showed 106 MPG, only a few hours later. Like mentioned above, go with an overall picture. WOT and headwinds kill fuel economy.

[illnoise]

because http://2strokebuzz.com/2012/05/29/25-fa ... nd-mileage

[jprestonian]

I find all this apt and hilarious... there's a dude on the PCX forum who thinks he's really going to know something special by running his PCX until it runs out of gas. I tried to tell him that that's not going to yield any more reliable data than doing the simple math involved, but he will not hear of it. "Oh, you don't KNOW the tank is 1.6 gallons, precisely." No, but I have a hard time believing that Honda's engineers wouldn't report it accurately enough to not make you have to push it ten miles to the next gas station. :lol:

People.
.

[Syd]

^^Ha. You should tell him he will only know for sure by doing the fill/run till empty at least twice. that way he'll have to push it twice!

[ericalm]

because http://2strokebuzz.com/2012/05/29/25-fa ... nd-mileage

THANK YOU.

[Capt_Don]

To specifically answer the last question, “Why am I not getting the mileage promised by the brochure?,” The answer is simple. The mileage figure quoted in the brochure IS attainable. All you need to do is lose 140 pounds, and ride on a perfectly level sheet of stainless steel, at 65°F with a 25mph wind at your back. Be sure not to accelerate, decelerate, or stop, and keep the engine at 1210 RPM, just above idle. Eventually you’ll work your way up to 25, maybe 30mph, but you’ll be getting great mileage.

I laughed really loud.

[PeteH]

The biggest factor for me seems to be long stretches vs. stop-and-go.

With enough fillups, overage vs. underage (attempting to get a nice meniscus of fuel in the little holes on the lower ring) will tend to average out over time.

That being said, when I commute back and forth from home to work every day, I tend to get about 75mpg. When I get the chance to take some longer 'country' rides on the weekend, I'm up over 90mpg. I haven't really ridden for any length of time whatsoever at WOT, so I don't have a feel for how much that knocks off the mileage.

I'm a heavy guy at 240 with a windshield - unfortunately that factor hasn't changed over the past couple of years, so it's now a control rather than a variable!

[Capt_Don]

The biggest factor for me seems to be long stretches vs. stop-and-go.

With enough fillups, overage vs. underage (attempting to get a nice meniscus of fuel in the little holes on the lower ring) will tend to average out over time.

That being said, when I commute back and forth from home to work every day, I tend to get about 75mpg. When I get the chance to take some longer 'country' rides on the weekend, I'm up over 90mpg. I haven't really ridden for any length of time whatsoever at WOT, so I don't have a feel for how much that knocks off the mileage.

I'm a heavy guy at 240 with a windshield - unfortunately that factor hasn't changed over the past couple of years, so it's now a control rather than a variable!

Yep!

I got close ot at WOT on the way to work sometimes, and if I am WOT for 60 miles (two days of round trips on the freeway) i get about 68 mpg, as opposed to 70 or 80.

[Edwub]

I think most people viewing this thread would agree that Blitzen (in his typical riding conditions) gets just over 50mpg consistently. [That chart shows 32 fill ups.]

Holy crap! That seems awful for a Blur 220i!

My Kymco People 250 got better than that at all stages of its life. And it's not even fuel-injected!
.

I get worse than other people in the Blur forum here do. I'm slightly heavier (~230, without gear), but much worse than that: I live in West Los Angeles. I am perpetually accelerating or braking, sometimes coasting. The city traffic commute kills me.

I knew that it would when I purchased the Blur, but I was also planning lots of fun trips. Sadly, I've been so busy with work, that I have taken barely any of the weekend fun trips I was planning (that would also probably bump up my MPG).

Checking Fuelly for other 220 Blurs (there are 6 listed: http://www.fuelly.com/motorcycle/genuine/blur%20ss220i ) they mostly get low to mid 60's for MPG. (There's also another Blur listed as a 220i, at 64).

Point of my post however was to show the data graph, it makes a pretty compelling case for my average. I drive the exact same commute every day, and I'm in LA so it's practically the exact same weather everyday. Not many outliers (other than the one long trip with the LASG) and the few MPG up/down each time very well are due to dozens of other factors,

because http://2strokebuzz.com/2012/05/29/25-fa ... nd-mileage

to Troutbum: just keep recording data!

[TomCat]

Personally, I don't understand the obsession with MPG. Reminds me of the hypermilers in their Prius's (is that plural for Prius?).
Have yet to check the MPG on my RH & probably never will. All I know is that I can make LOTS of trips & have LOTS of fun doing it on a gallon of gas.
Which is why I bought it.

[Capt_Don]

Personally, I don't understand the obsession with MPG. Reminds me of the hypermilers in their Prius's (is that plural for Prius?).
Have yet to check the MPG on my RH & probably never will. All I know is that I can make LOTS of trips & have LOTS of fun doing it on a gallon of gas.
Which is why I bought it.

I never checked on my arrow either, but I think I check mine because it is fun. I don't use Fuelly, just a spreadsheet I got of the internet, but I enter my gas, my miles, and how much I spent on it every couple days. I just enjoy doing it... come to think of it, I don't know why.

[BeefSupreme]

My Like 200i fluctuates too. My averaging is 71.4 mpg. My highest was 81, lowest 62. I'm 6ft 190lbs. Me and the ladyfriend do lots of 2UP riding. On the weekends we go for some long rides through the country. I've compared it all and this is pretty much what mine is giving me: 1UP city riding I get around 70. 1UP highway about 80. 2UP city 65. 2UP highway 70.

As for filling it up, do it exactly the same every time. I put mine on the centerstand and fill it up just until the "overfill bar" is covered to the top. No more.

[Syd]

Personally, I don't understand the obsession with MPG. Reminds me of the hypermilers in their Prius's (is that plural for Prius?).
Have yet to check the MPG on my RH & probably never will. All I know is that I can make LOTS of trips & have LOTS of fun doing it on a gallon of gas.
Which is why I bought it.

It's not always just to get higher mpg. For me it generates a baseline from which comparisons can be made. If my long term fuel usage is in decline, that most likely points to something wearing out or going bad. If you ride the same way all the time, you may not notice it in daily riding, but if you keep track, it is visible, and can be used. For example, I noticed the fuel usage increasing for months before I noticed a difference in acceleration and top end, and decided after 15000 miles it was time for a new belt/rollers (the rollers especially were nearly completely worn down.

For those who obsessively fill to the same level and keep track as well; there's no need, because it all averages out in the end. Tank to tank graphs may vary, but 5 tank to 5 tank averages will still be roughly the same.

[iMoses]

The biggest contributor to my MPG's is my riding style.

I did a ride on my Buddy 125 in which I had the smallest cc's, I was WOT almost the entire 50 mile trip (and 50 miles back). Horrible MPG. A few weeks later I was with a group 50cc scoots (around 60 miles total)...GREAT MPG!

[TVB]

It's not always just to get higher mpg. For me it generates a baseline from which comparisons can be made. If my long term fuel usage is in decline, that most likely points to something wearing out or going bad.

Same here. When I noticed that my gas mileage was getting bad, and I couldn't blame cold weather, I took it in for service and they got it back in trim.

And I like knowing that I can brag that I get "over 80mpg".