Inconsistent Gas Mileage

[pugbuddy]

My gas mileage has gone crazy lately. I'm still averaging a very healthy 96.7 mpg but I cannot figure out why every other ride is so low (or high)! My recent mileage (per Fuelly):

96.9...78.3...95.9...76.1...105.9....

I'm not doing anything different on a week-to-week basis. Riding to and from work and errands around town! Any ideas as to why it is so inconsistent?

[jijifer]

My gas mileage has gone crazy lately. I'm still averaging a very healthy 96.7 mpg but I cannot figure out why every other ride is so low (or high)! My recent mileage (per Fuelly):

96.9...78.3...95.9...76.1...105.9....

I'm not doing anything different on a week-to-week basis. Riding to and from work and errands around town! Any ideas as to why it is so inconsistent?

back on the 125 or is this still the 170? Have some weeks been hotter than others?

[desmolicious]

and are you sure you are filling it up to the same level each time?
Sometimes the exact same gas pumps I use click off sooner than other times.

[pugbuddy]

@ JJ - this is the 125. The last two weeks have been much cooler but the roller coaster has not stopped.

@desmolicious - I fill it till it clicks. It shouldn't make that big of a difference in the mileage, although it may affect it some.

[jd]

If I filled my tank only until "it clicks," then I wouldn't be putting much gas into it. Lifting the nozzle up a bit causes the "click" to come later, but it's hard to be consistent with that routine.

What I do is wait until it "clicks," and then lift the nozzle pretty high and add gas very slowly until it starts to come through the little holes surrounding the main filler hole. I stop right there and I'm getting very consistent fuel economy...on TWO Buddy 125s! They both get around 110 MPG consistently.

BTW, I buy gas based on the miles covered, not the reading on the silly gas gauge, which shows I'm running on fumes when I still have more than a half-gallon remaining. So I'm usually buying at least 1.2 to 1.3 gallons at a time.

jd

[michelle_7728]

I think .94 is the most I have ever put in my Buddy in 4,600 miles. Hmmm...maybe I'm just being a bit cautious and filling up sooner than I need to.

[bluebuddygirl]

@desmolicious - I fill it till it clicks. It shouldn't make that big of a difference in the mileage, although it may affect it some.

It can affect the mileage tremendously with such a small tank. The only true gas mileage is the average over several fill ups. Trying to average each tank is pointless.

Also, filling it till it clicks will vary depending on that particular nozzle and the rate of flow, and the rate varies depending on how full the tank is at the station. Too many variables.

[jijifer]

when I go to empty, I'm always filling it somewhere btwn 1.1 and 1.2 never more than 1.2 has been needed.

we have the vapor collars but I have the mccuff but for sure the nozzle "clicks" and shuts off short of full. I always peak and go to the built in ledge. that's usually the 2nd click.

I'd suggest double checking how much you're filling time to time because that could be the diff.

[Lil Buddy]

There are too many variables working against you to get a true MPG number. Temperature, time of day, traffic flow, weight carried on the scoot and even your parking spot will change the numbers. And with the fuel tank being so small, even a few ounces more than what the pump reads can cause inconsistencies.

Ever watch Mythbusters when they check MPG? They make sure every last detail is controlled and identical. So unless you want to pump your gas into a separate container first, and then weigh it to confirm it’s actually X number of gallons, then park and drive in a temperature controlled environment with no other traffic going the exact same speed and on the exact same route each time….. I would suggest you just , ride, refuel and repeat. And enjoy your 90 something MPG.

[robby]

My money is on measurement error. If your average fillup is 1 gallon, a difference of 2 cups of gas would be the difference between 70 MPG and 90. If you're doing it until the gas level triggers the pump stop, that could be as simple as a change in the incline at which your scooter is parked.

I had the same problem when I filled up single tanks at gas stations. My readings have become a lot more accurate since I started refilling 5 gallons at a time via an auxilliary tank.

[k1dude]

My recent mileage (per Fuelly):

96.9...78.3...95.9...76.1...105.9....

You're milage consistancy is better than mine. I've ranged from 64 to 107 basically doing the same riding.

[pugbuddy]

By my mileage, I mean Miles Per Gallon, not how many miles I ride. That's why when the gas shuts off doesn't really matter--it's not based on how far I ride; it's how far I get per gallon of gas.

I'm getting 70-something miles per gallon followed by 90-something miles per gallon every other week. That 20 miles-per-gallon swing doesn't make sense to me....

[goldscott]

I have a 125 and have been tracking my MPGs on Fuelly (see my signature) for the past 12000 miles or so.

I get lower MPGs on trips when I'm going WOT 90% of the time.

[pugbuddy]

I track on Fuelly as well. I'm just confused by the highs and lows of my mileage since my weekly riding habits don't vary much.

[Syd]

IMO, unless you see a decline in overall mileage (I mean over the life of the scoot), I would ignore any tank to tank differences. As others have said, it's too easy to see differences when you are just comparing one tank to the next.

[dshanson]

I think .94 is the most I have ever put in my Buddy in 4,600 miles. Hmmm...maybe I'm just being a bit cautious and filling up sooner than I need to.

same for me hahahha.

I noticed that yesterday I only got 80 mpg from my fill up, which was alarming to me cuz I was getting 105 before....waaaaaah my average mpg is down to 96 (:P). now, ive only had my scooter for a little over 2 weeks, but I share your concern.

but yeah, in the end, 96 is better than my corolla's 32

[jd]

I think .94 is the most I have ever put in my Buddy in 4,600 miles. Hmmm...maybe I'm just being a bit cautious and filling up sooner than I need to.

same for me hahahha.

I noticed that yesterday I only got 80 mpg from my fill up, which was alarming to me cuz I was getting 105 before....waaaaaah my average mpg is down to 96 (:P). now, ive only had my scooter for a little over 2 weeks, but I share your concern.

but yeah, in the end, 96 is better than my corolla's 32

Fuel consumption on these simple bikes does not vary by 25 percent from tank-to-tank. I've been riding mopeds and scooters with engine sizes ranging from 49cc to 125 cc for many years. Riding habits and ambient conditions will affect consumption, but not to that magnitude if the engine is running right.

Measured variances like that are caused by inconsistent filling practices. If you are unable to fill the tank to approximately the same level each time (because of varying locations, pumps, gas nozzles, or, most likely, lack of patience), then don't pay attention to the measurement on an individual tank. It will just make you crazy, and it's not an accurate number, anyway. Keep track of each tank, but calculate MPG only on a cumulative basis (at least five fill-ups at a time.)

It's not that hard to get the fill level the same each time if you pay attention, but it's not important unless you're obsessing about each tank's MPG. I'm obsessive, so I'm careful about the filling, and the MPG calculations are, as a result, quite consistent not only from tank-to-tank, but between our two Buddy 125s as well.

[KABarash]

but yeah, in the end, 96 is better than my corolla's 32

Honestly, I don't really worry about it, I roughly figure I'm getting 90mpg. THAT'S a 'poo-load' and a half better than the 18-20 my Jeep YJ gets!!!!!

[bluebuddygirl]

By my mileage, I mean Miles Per Gallon, not how many miles I ride. That's why when the gas shuts off doesn't really matter--it's not based on how far I ride; it's how far I get per gallon of gas.

But as others have stated your Miles per Gallon are based on how many Gallons you use, and if your measurement of how much you have used is based on how much you put into your tank then we are talking about the issue that you have mentioned. The point is that if you cannot tell EXACTLY were the gas is hitting on the tank with precise conditions each time (level ground) then you cannot make any accurate Miles Per Gallon calculations on one tankful, so your belief that you are alternating good and bad mileage is negated.

[dshanson]

end of the world. my average mpg went down to 95, from 96. D: I guess it will begin to even out more....but I hope it goes up. Maybe its because I just had my first maintenance? would that effect gas mileage?

[michelle_7728]

I think .94 is the most I have ever put in my Buddy in 4,600 miles. Hmmm...maybe I'm just being a bit cautious and filling up sooner than I need to.

same for me hahahha.

I noticed that yesterday I only got 80 mpg from my fill up, which was alarming to me cuz I was getting 105 before....waaaaaah my average mpg is down to 96 (:P). now, ive only had my scooter for a little over 2 weeks, but I share your concern.

but yeah, in the end, 96 is better than my corolla's 32

Fuel consumption on these simple bikes does not vary by 25 percent from tank-to-tank. I've been riding mopeds and scooters with engine sizes ranging from 49cc to 125 cc for many years. Riding habits and ambient conditions will affect consumption, but not to that magnitude if the engine is running right.

Measured variances like that are caused by inconsistent filling practices. If you are unable to fill the tank to approximately the same level each time (because of varying locations, pumps, gas nozzles, or, most likely, lack of patience), then don't pay attention to the measurement on an individual tank. It will just make you crazy, and it's not an accurate number, anyway. Keep track of each tank, but calculate MPG only on a cumulative basis (at least five fill-ups at a time.)

It's not that hard to get the fill level the same each time if you pay attention, but it's not important unless you're obsessing about each tank's MPG. I'm obsessive, so I'm careful about the filling, and the MPG calculations are, as a result, quite consistent not only from tank-to-tank, but between our two Buddy 125s as well.

Oh, I get to the metal fill level each time (I do the slow click until it gets there). ...and I'm not complaining about inconsistent mileage...we probably all get it to a certain extent. I was just saying that I don't think I've ever put more than .94 or maybe a gallon max in at a time. I'm sure I could run it longer before filling up, but I prefer to fill it up sooner so I don't have to ever risk that "walk of shame".

dshanson - I have a Corolla too. Nice car, and pretty good gas mileage, but you're right - no where near what the Buddy gets!

[roblinx]

I'm guessing it has to do with metering variations combined with small differences in fill level, temperature, etc. This is strictly a guess: I know the gas pumps are calibrated and certified, but there's still going to be variation, and it will be more pronounced at the slower fill rate we small-tankers tend to use. Combine that with slight differences in fill level, density differences due to temperature...

Consider the math. A gallon is 128 ounces. 5 one-hundredths of a gallon will be 6 ounces--a standard glass of wine. Easily within the range of typical variances mentioned above. So, let's say you go 90 miles, and you fill what the pump says is 1 gallon.

90 / 1 = 90 mpg

If the reading says 1.05, you'd think you got 90 / 1.05 = 85.7 mpg

If the reading says .95, you'd think you got 90 / 0.95 = 94.7 mpg

That's a variation of 10 mpg based on a very small amount of gas.

[mikebuddy]

what gas do you use, I usually run premium gas, its worth the 2 or 3 cents extra.

[jd]

what gas do you use, I usually run premium gas, its worth the 2 or 3 cents extra.

No, it's not.

"Premium" gas is not better than regular gas. It just has additives to make the gas more difficult to ignite so it doesn't do it prematurely, which is an issue only in very high compression engines in which the fuel is likely to detonate early, or "ping." These engines don't have very high compression.

Unless you hear "pinging" (which is pretty hard to imagine from a stock scooter engine) then you're getting absolutely no value from the premium gas. The gas station is, though. Of course, if you REALLY want to waste money at the gas station, buy some cigarettes or lottery tickets while you're there.

[michelle_7728]

what gas do you use, I usually run premium gas, its worth the 2 or 3 cents extra.

No, it's not.

"Premium" gas is not better than regular gas. It just has additives to make the gas more difficult to ignite so it doesn't do it prematurely, which is an issue only in very high compression engines in which the fuel is likely to detonate early, or "ping." These engines don't have very high compression.

Unless you hear "pinging" (which is pretty hard to imagine from a stock scooter engine) then you're getting absolutely no value from the premium gas. The gas station is, though. Of course, if you REALLY want to waste money at the gas station, buy some cigarettes or lottery tickets while you're there.

Gas thread.

[jd]

I'm relatively new to this forum so I hadn't seen the Gas Thread. I'm relieved to know that my amateur opinion seems to jibe with the experts'. Phew!