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After returning from our last summer road trip in September I noticed an apparently sudden and surprising increase in gas milage the first tank back. During the trip I pushed my 06 Wee the hardest ever--2 up with full side bags averaging 75 mph against a 10-15 mph head wind with peak passing speeds of 83.4 (GPS) [yes, VEE-guys, there were a few pucker moments when I really would have liked your extra 350 cc!]). Thought might have been filling fluke so decided to reevauate after 4 full tanks. Sure enough, a real increase in gas milage. Then decided to go back and check the first 4 tanks after summer touring the past 5 years to see if there was a trend. Thought this would be more consistent since all city riding (I ride year-round here in Seattle) while summer touring has significant variations in route, speed and headwind. I was stunned by what I found:

Mileage MPG
3,488 45.87
7,300 46.57
11,077 48.80
18,656 50.05
25,149 51.15

Every year, city driving gas mileage (averaged over 1,000 miles) consistently increased so that after 25k of riding it had gone up a remarkable 12%!

Nothing was changed with the engine and all the maintenance was done by the dealer (except some oil changes) on time according to the manual. I admit to not being an agressive rider--first set of tires lasted 16k miles. (+2 teeth on drive sprocket, BTW)

Does it really take this long to break in a Wee?
 

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Nothing to do with break-in I guess.
You were just riding "harder" which means riding it hard enough.
I've stopped using 6th gear and fount that my fuel consumption went down now that I do highway in 5th and 4th.
I guess the engine is more efficient at higher rpm (especially when combined with a lighter load)

6th is really just for maintaining speed; downshift if you need/want to accelerate.
 

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You went up 2 teeth on the countershaft?

or the driven sprocket on the wheel

I think mechanical systems get looser and looser then too loose
 

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ng 75 mph against a 10-15 mph head wind with peak passing speeds of 83.4 (GPS) [yes, VEE-guys, there were a few pucker moments when I really would have liked your extra 350 cc!])


17-tooth drive sprocket, so actually lower RPM. Was put on by the dealer by my request at delivery


fwiw, that 17t sprocket is prolly hurting your fuel economy and yer safety reserve of quick acceleration

fuel economy is dependent on throttle opening not rpm



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fwiw, that 17t sprocket is prolly hurting your fuel economy and yer safety reserve of quick acceleration
I hated the torque loss going to 16T, can't imagine how wimpy it is with a 17T. Best tank this year was 59.66mpg. There was a 39mpg tank on the same trip.
 

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Don't know the exact reason obviously.

My idea is that when you first got the Wee, you were careful and a bit more conservative. Which on a 17t Counter sprocket means you weren't pulling many RPMs. Possibly the result of this was a bit of Carbon and deposit buildup. Which over time could reduce mileage a bit.

Then, as you gained more familiarity with your bike and become more comfortable with not just your DL650's handling characteristics but your own skill level as well you have ridden a bit harder. Thus cleaning out some carbon etc. deposits.

As this happened and you learned when not to upshift and what gear to keep your bike in when you pass and take corners etc., you ended up increasing your gas mileage.

Just a thought. I am not a mechanic in way, shape or form.
 

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If you ride around in 4th then 17 tooth cum se cum sa

Lower engine speed results in lower engine internal friction loss and makes for higher combustion processes that are more efficient. Hence overdrive.

All the tuning of an engine/bike has assumptions such as normal operating speeds etc. hopefully to maximize most MPG at normal conditions. These factors probably overwhelm the slow engine speed pluses.
 

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I think Randy is correct. Where and how you drive matter most. I have had the best mpg using gas from Canada, and the worst out west on posted 75 (95 indicated).

I have not played with gearing on the Strom, but on my drz400s it increased my mpg when lowered my gearing. Seemed odd at the time to me, but I heard alot of reasons for it. It was also odd to me that there was no decrease in my top speed, it just revs higher.
 

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It might be the gas. I found I got nearly 20% better gas mileage in mexico. My guess is that there's no ethanol in their fuel. Also, as time goes on maybe your riding habits are easing up?
 

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It might be the gas. I found I got nearly 20% better gas mileage in mexico. My guess is that there's no ethanol in their fuel. Also, as time goes on maybe your riding habits are easing up?
Ethanol has 66% of the energy of gasoline and is only 10% of the fuel. No way does that account for 20% better mileage. Warmer, less dense air and grease that is not as stiff helps along with fuel mixtures not being as volatile as with the benzine in fuel in cold weather areas and times. Riding style make a difference too.
 

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I have recorded my mileage on my 2006 DL650 for 202,000 km, roughly 125,500 miles.

I have noticed that overall two things make a significant difference in fuel consumption. That is speed and temeprature. Higher speeds (in particular airspeed) and lower temperatures reduce mileage. Was the temperature higher when you got better mileage?

Here is my graph of mileage since I got the bike in the summer of 2006. I suspect the overall drop in mileage relates to a much harder riding style.



The higher overall areas corespond to summer months and warm weather riding and lower parts correspond to winter riding, while the short term fluctuations corespond to higher speed riding (generally 75 to 85 mph. The peaks correspond to longer rides (usually in the USA) where my average speeds were lower as I tend to do secondary roads down there.

..Tom
 

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Ethanol lowers combustion temperature and pressure which does lower efficiency

Most important is it does cost you in the real important

Dollars per Mile is down 20% from Real Gasoline

I am not sure but organic molecules can have double bonds which release almost twice the energy. I am sure they don't allow much benzene as it is believed to be a carcinogen
 

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Ethanol lowers combustion temperature and pressure which does lower efficiency
Would running a higher engine temperature help efficiency? Lets say shooting for 4 bars instead of the usual constant 3. Is the coolant pump always running or just when the engine temperature calls for it?

How bout covering part of the radiator to get a higher engine temperature. More in winter months, less in summer months.

Would higher engine (within a reasonable range) temps lower engine life?

My average mpg went from 54 to 49. I blame the proliferation of ethanol.
 

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Lowers COMBUSTION chamber temperature and efficiency but yes if the entire motor ran hotter it would be more efficient so your sarcasm is also right.

Hot weather short runs are better because it gets off of the enriching setting faster.
 

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Lowers COMBUSTION chamber temperature and efficiency but yes if the entire motor ran hotter it would be more efficient so your sarcasm is also right.

Hot weather short runs are better because it gets off of the enriching setting faster.
Were you replying to me? Nothing I said was sarcasm. In fact I think I might try it come this spring, blocking off half of the radiator. Of course that would only be effective if the water pump runs continuously unlike the fan.

Your statement of short runs are better but also say a hotter engine would be more efficient seems contradictory if what you mean by short runs is allowing the engine to cool back down.
 

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Would running a higher engine temperature help efficiency? Lets say shooting for 4 bars instead of the usual constant 3. Is the coolant pump always running or just when the engine temperature calls for it?

How bout covering part of the radiator to get a higher engine temperature. More in winter months, less in summer months.

Would higher engine (within a reasonable range) temps lower engine life?

My average mpg went from 54 to 49. I blame the proliferation of ethanol.

I'm pretty sure the fuel injection sprays more fuel in during colder air temps to compensate for poorer fuel atomization (we don't have intake air pre-heaters.) I don't believe the temperature of the motor itself affects this (although the colder engine has higher friction with thicker oil; that's one reason why it is better to start and ride immediately instead of sitting there idling to warm up.)

BTW, fuel pumps at gas stations (at least the ones I go to) compensate for the temperature of the fuel when pumping as they effectively pump by weight (cold fuel is heavier per unit of volume measure) so you aren't actually getting as much volume of fuel and (at least where I live) we have winter fuel which doesn't seem to give as good mileage as summer fuel.

..Tom
 
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