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Discussion Starter #1
So I go to the gas station this afternoon on the way home from work. I pull up & do my thing. I put 5.1-something gallons in after going 210.6 miles. For me this was pushing it since I do quite a bit of interstate running during my commute. Anyway, the point is that...from the last tank to this one....my mileage went up 4 mpg! I got around 36mpg on the last tank & 40mpg this tank! :jawdrop: Now, the only thing that's changed is that I recently had some work done on the bike. New rear brakes & chain. The only reason I "had work done" is because I don't have the tool to break the chain. I HAVE noticed that she's been pulling REAL HARD with the new chain on! :hurray:

So, other than the new hardware & filling up at a different gas station than usual with the same grade of gas, does anyone know of any reason why this is the case? Trust me....I'm not complaining at all!!! Just curious......
 

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Living the Stereotype
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Bye bye winter formula.

or

The oil companies are feeling guilty for their near-record quarterly profits and decided to increase the hydrocarbons in their products.
 

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Discussion Starter #5
You don't own an angle grinder?
No. But from what I kinda know getting the new chain back together can be a pain. I have quite a bit of experience with road racing bicycle chains. I know a motorcycle chain isn't all that much different. Just a LOT bigger! I figure when you're spending that much on a chain might as well not mess it up! :biggrinjester:
 

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Discussion Starter #6
Bye bye winter formula.

or

The oil companies are feeling guilty for their near-record quarterly profits and decided to increase the hydrocarbons in their products.
Do you really think it's as simple as a change in the gasoline formula? I've honestly never paid any attention to it.

As for the oil companies feeling guilty.....that's a good one!!!! :green_lol:
 

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Was it warmer on the last tank? Our bikes get better mileage in warmer weather.

But one tank really isn't enough to tell if mileage has actually increased as there can be too much effect of slight differences in filling.

..Tom
 

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Discussion Starter #9
Was it warmer on the last tank? Our bikes get better mileage in warmer weather.

But one tank really isn't enough to tell if mileage has actually increased as there can be too much effect of slight differences in filling.

..Tom
Windy then quiet?
No. the temp actually dropped while I was running that tank. I also understand that just one tank isn't enough to know if there's a trend or not. I'm gonna keep an eye on it for sure.

As for the wind...no. The wind has increased over the last few days. I'm into the next tank now so we'll see how it goes.
 

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So I go to the gas station this afternoon on the way home from work. I pull up & do my thing. I put 5.1-something gallons in after going 210.6 miles. For me this was pushing it since I do quite a bit of interstate running during my commute. Anyway, the point is that...from the last tank to this one....my mileage went up 4 mpg! I got around 36mpg on the last tank & 40mpg this tank! :jawdrop: Now, the only thing that's changed is that I recently had some work done on the bike. New rear brakes & chain. The only reason I "had work done" is because I don't have the tool to break the chain. I HAVE noticed that she's been pulling REAL HARD with the new chain on! :hurray:

So, other than the new hardware & filling up at a different gas station than usual with the same grade of gas, does anyone know of any reason why this is the case? Trust me....I'm not complaining at all!!! Just curious......
On these bikes, it's amazing how much MPG difference can be seen from small changes. I just got back from a 1500 mile trip. My mileage, from constant cruising at 75-80 mph, varied from 34MPG on my worst tank....to 47MPG on my best. California (the we're gonna save the planet state) gas is only slightly better than pure horse pi$$. Depending on riding style, I've seen my full-tank mileage vary from 29 to 49. On my KLR, I've never seen less than 45 or higher than 51.
 

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On fuel efficient machines a couple of tenths one way or the other really skew the results. I average mine out so I don't get too discouraged with a real low tank.
 

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You prob got a real tank of Petro without much ethanol? That would be my guess.

My Vee averages around the 46 mpg range from my daily commuting, when I decide to check the MPGs. :mrgreen:
 

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Discussion Starter #13
Well....after going through a tank & a half (had to top off this weekend & didn't write down the mileage :headbang:) I wrote down the mileage for the full tank. I got 33mpg. :confused: The variables were as follows:

- Riding in the mountains at slower speeds with some high speed stretches
- Running ALL DAY
- Weather started out cool/wet then got warmer as the day went on
- Filled up at a Shell station

The 40mpg tank I filled up at a Wawa. Don't really know if that has a LOT to do with it, but it seemed worth mentioning. I've recently filled up at the same Wawa yesterday morning on the way to work. I'll keep you posted on how this tank goes.
 

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Ethanol is PRE burnt fuel

It cost 15% more and gives 10% less mileage another triumph in tree hugger technology.

But heck its starving Mexicans so they want to come here more
 

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It cost 15% more and gives 10% less mileage
It costs a little less at the pump. Its cost to manufacture is a huge debate. It has only 66% of the heat energy of gasoline, not 90%.
 

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Bye bye winter formula.
Why do I keep hearing about this mysterious "winter formula" ?
A buddy of mine owns a Shell station in Montreal, and he says the gasoline is the same regardless of the season.

Makes sense too; why would there be a need for a different formulation in winter? It's not like gasoline freezes...

Maybe the whole "winter formula" confusion is due to the fact that diesel comes in multiple "flavours".
 

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Ethanol is PRE burnt fuel

It cost 15% more and gives 10% less mileage another triumph in tree hugger technology.

But heck its starving Mexicans so they want to come here more
I don't know if ethanol is better or worse. Hopefully it makes us less dependent on foreign oil. This isn't being pushed by tree huggers as much as farm states being funded by the agribusiness. Ethanol isn't necessarily environmentally friendly.
 

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You may very well have winter blend all year in Montreal.

Taken from here: The Oil Drum | Refining 101: Winter Gasoline I know in NJ we had seasonal changes, here in VA I think so as well.

"A Primer on Gasoline Blending
Gasoline is composed of many different hydrocarbons. Crude oil enters a refinery, and is processed through various units before being blended into gasoline. A refinery may have a fluid catalytic cracker (FCC), an alkylate unit, and a reformer, each of which produces gasoline blending components. Alkylate gasoline, for example, is valuable because it has a very high octane, and can be used to produce high-octane (and higher value) blends. Light straight run gasoline is the least processed stream. It is cheap to produce, but it has a low octane. The person specifying the gasoline blends has to mix all of the components together to meet the product specifications.

There are two very important (although not the only) specifications that need to be met for each gasoline blend. The gasoline needs to have the proper octane, and it needs to have the proper Reid vapor pressure, or RVP. While the octane of a particular grade is constant throughout the year, the RVP spec changes as cooler weather sets in.

The RVP is the vapor pressure of the gasoline blend when the temperature is 100 degrees F. Normal atmospheric pressure varies, but is usually around 14.7 lbs per square inch (psi). Atmospheric pressure is caused by the weight of the air over our heads. If a liquid has a vapor pressure of greater than local atmospheric pressure, that liquid boils. For example, when you heat a pot of water, the vapor pressure increases until it reaches atmospheric pressure. At that point, the water begins to boil.

In the summer, when temperatures can exceed 100 degrees F in many locations, it is important that the RVP of gasoline is well below 14.7. Otherwise, it can pressure up your gas tanks and gas cans, and it can boil in open containers. Gas that is boiled off ends up in the atmosphere, and contributes to air pollution. Therefore, the EPA has declared that summer gasoline blends may not exceed 7.8 psi in some locations, and 9.0 psi in others.

A typical summer gasoline blend might consist of 40% FCC gas, 25% straight run gas, 15% alkylate, 18% reformate, and 2% butane. The RVP of the gasoline blend depends on how much of each component is in the blend, and what the RVP is of each component. Butane is a relatively inexpensive ingredient in gasoline, but it has the highest vapor pressure at around 52 psi.

In a gasoline blend, each component contributes a fraction to the overall RVP. In the case of butane, if there is 10% butane in the blend, it will contribute around 5.2 psi (10% of 52 psi) to the overall blend. (In reality, it is slightly more complicated than this, because some components interact with each other which can affect the expected RVP). This means that in the summer, the butane fraction must be very low in the gasoline, or the overall RVP of the blend will be too high. That is the primary difference between winter and summer gasoline blends.

"
 

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I see... so the theory is that with less butane in the gas, we will get better mileage.
I haven't done the math, but while it makes some minimal sense, it does not explain the winter/summer mileage difference, as the energy difference would be so small as to be negligible.

I think the mileage difference between summer and winter is not due to the difference in fuel blends, but to the difference in air temperatures.

Colder air is denser, and when the ECU sees colder/denser air, it adds more fuel to the mix. That's really all there is to it.

When there is a simple solution to the problem, there's no need to look for a more complicated one.
 

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When there is a simple solution to the problem, there's no need to look for a more complicated one.
I'm sure that is the largest factor. I wonder also how much the difference in in the way fuel is metered makes as well.

The volume of fuel pumped is compensated for by the temperature it is pumped at, you are actually paying for fuel by weight. If you pumped a gallon of gas at 20C (68 F) it might measure as exactly a gallon by volume. In hot summer the gallon pumped would measure larger than a gallon, and in the cold it would measure less than a gallon. The fuel system only meters the volume of gas and sprays more fuel in cold temperature because of poorer atomization of the fuel (as you mention) so we have a fuel system that is spraying larger amounts of gas but the tank is actually filled with less gas than we think.

On top of that lower tire pressures, longer times for the motor and the other moving parts on the bike cause higher friction, and the denser air increases aerodynamic drag.

All the above would tend to multiply the effect, so that while one by itself may not make a huge difference, all multiplied together can make a large difference. (Three things that individually made a 3% change in mileage would make a 12.5% reduction altogether if I did the math correctly.)

My records over 155,000 km show a drop of 10 to 20% in fuel mileage at temperatures around freezing vs. summer hot temperatures. (Someone that understands statistical analysis could tell me the actual variation I'm sure.)

..Tom
 
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