Gas Mileage vs Lean/Rich Fuel Mixture
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Road Captain
Joined: Jun 2009
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From: North Carolina
Gas Mileage vs Lean/Rich Fuel Mixture
I keep track of my miles and the amount of fuel required to fill up to get an accurate mileage for my bike.
It used to be around 50 mpg but after switching air cleaners, it seems to have dropped a little to about 48 mpg. This could very well be due to the fact that my driving habits have changed (run bike in lower gear and higher RPM) but if we were to assume that driving habits remain constant, what would this mean in terms of the fuel mixture being lean or rich? Is there even a correlation?
Also, could it be the case that despite the lower mpg, the bike is closer to the peak performance of the a/c and exhaust combo?
It used to be around 50 mpg but after switching air cleaners, it seems to have dropped a little to about 48 mpg. This could very well be due to the fact that my driving habits have changed (run bike in lower gear and higher RPM) but if we were to assume that driving habits remain constant, what would this mean in terms of the fuel mixture being lean or rich? Is there even a correlation?
Also, could it be the case that despite the lower mpg, the bike is closer to the peak performance of the a/c and exhaust combo?
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Road Captain
Joined: Jun 2009
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From: North Carolina
Ok..that's what I thought.
Is gas mileage highest at the peak performance or could it be the case that my bike was running a bit lean before and now it's closer to being mapped correctly?
Is gas mileage highest at the peak performance or could it be the case that my bike was running a bit lean before and now it's closer to being mapped correctly?
Road Master
Joined: Sep 2010
Posts: 1,077
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There is a "sweet spot" as far as mileage is concerned. Going leaner doesn't always = better mileage and richer doesn't always = worse. I've had bikes that actually improved MPG's from going richer. If it's too lean it will not run as efficiently as it should and it will also run hot. Obviously, going too rich will drop MPG's pretty dramatically as well.
Most likely, your MPG loss is due to riding habits. Running just a little more aggressively will drag the mileage down by a significant margin.
Most likely, your MPG loss is due to riding habits. Running just a little more aggressively will drag the mileage down by a significant margin.
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
I keep track of my miles and the amount of fuel required to fill up to get an accurate mileage for my bike.
It used to be around 50 mpg but after switching air cleaners, it seems to have dropped a little to about 48 mpg. This could very well be due to the fact that my driving habits have changed (run bike in lower gear and higher RPM) but if we were to assume that driving habits remain constant, what would this mean in terms of the fuel mixture being lean or rich? Is there even a correlation?
Also, could it be the case that despite the lower mpg, the bike is closer to the peak performance of the a/c and exhaust combo?
It used to be around 50 mpg but after switching air cleaners, it seems to have dropped a little to about 48 mpg. This could very well be due to the fact that my driving habits have changed (run bike in lower gear and higher RPM) but if we were to assume that driving habits remain constant, what would this mean in terms of the fuel mixture being lean or rich? Is there even a correlation?
Also, could it be the case that despite the lower mpg, the bike is closer to the peak performance of the a/c and exhaust combo?
If you changed to a higher flowing A/C and didn't remap or add a tuner, your bike is going to be running leaner, if fact, too lean.
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Road Captain
Joined: Jun 2009
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From: North Carolina
I bought this bike used and when I bought it, the previous owner had an after-market iron cross A/C on the bike. He mentioned to me that he had the ECM re-mapped (didn't really ask any further questions because at the time I really had no idea about anything) but then also gave me the spare SE Stage 1 A/C as well.
This is all just me guessing, but I'd think that he initially upgraded to Stage 1 and had the SE Stage 1 A/C on and had the ECM remapped and then at a later time, decided to purchase the iron cross A/C and just slap it on there without doing another remap.
I rode with the iron cross A/C until the damn thing flew off riding down the highway and had to put on the SE Stage 1 A/C and this is were the mpg decreased slightly and I'm trying to figure out what the deviation means.
But, as mentioned, it could all just be a waste of time and the decrease due to my riding habits, although I don't think that's the case because the last tank I drove very conservatively like I used to, all highway miles and the mpg was still about 2 mpg less than before. Not a huge deal but mainly I'm just trying to figure out if despite the decrease in mpg, I'm closer to the ideal fuel/air mixture if the ECM was indeed remapped with the SE Stage 1 A/C.
It *feels* like the bike is riding slightly smoother and better but that's so subjective that I kind of throw it out of the equation.
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Stellar HDF Member
Joined: May 2007
Posts: 3,254
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From: USA
You may wish to remove your sparks plugs.
Do they appear tan or white or black?
That will tell you if you are close to tune, lean or rich.
Yep, increased air through the intake, without increase fuel mixture equals lean. Who know what that Iron Cross filter was doing?
Do they appear tan or white or black?
That will tell you if you are close to tune, lean or rich.
Yep, increased air through the intake, without increase fuel mixture equals lean. Who know what that Iron Cross filter was doing?
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Thread Starter
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Road Captain
Joined: Jun 2009
Posts: 642
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From: North Carolina
You may wish to remove your sparks plugs.
Do they appear tan or white or black?
That will tell you if you are close to tune, lean or rich.
Yep, increased air through the intake, without increase fuel mixture equals lean. Who know what that Iron Cross filter was doing?
Do they appear tan or white or black?
That will tell you if you are close to tune, lean or rich.
Yep, increased air through the intake, without increase fuel mixture equals lean. Who know what that Iron Cross filter was doing?
Account Deactivated
Joined: Oct 2009
Posts: 1,757
Likes: 8
From: Central Florida
Sweet spot,,,,
There is a "sweet spot" as far as mileage is concerned. Going leaner doesn't always = better mileage and richer doesn't always = worse. I've had bikes that actually improved MPG's from going richer. If it's too lean it will not run as efficiently as it should and it will also run hot. Obviously, going too rich will drop MPG's pretty dramatically as well.
Most likely, your MPG loss is due to riding habits. Running just a little more aggressively will drag the mileage down by a significant margin.
Most likely, your MPG loss is due to riding habits. Running just a little more aggressively will drag the mileage down by a significant margin.
Box stock 08 1200R,,Hi-way miles 47 avg mpg trying to hold 70-75 mph
Added the X14ieD Inline O2 resistors and It's suppose to take my stock
lean 14.7 AFR down to 14.0 AFR In closed loop mode,,
where we mostly ride,,
Getting a solid 49 mpg,,,,But !..there is Always a variable,,,
I cleaned the stock Air filter In the dishwasher,,,It only had
4,000 miles on It and was not that Dirty.
But I must assume It Is a factor.
I seem to get a smoother power delivery,,feels more efficient.
So I'm probably using a bit less throttle.
The site said I'd loose 4 to 5 % of my mileage,,,
http://www.nightrider.com/parts/
Best 100 bucks I ever spent,,now I can Add the Rush slip on's an get
a decent sound without all that risky Dyno time and money.
I don't want or need that last ounce of power and don't think,
IMO a Stage one Air filter makes that much difference to warrent all that coin
for dyno time and ecm mods.
I just want a little richer AFR so I can add good sound,,,,
Last edited by Osco; Oct 10, 2010 at 12:00 PM.
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