Poor Milage When Cold/Cool Out

[fattony]

I have a theory.....

Just made a run to Ashville, and had a chance to take a good look at my fuel economy.

What I found is that in the morning, when it was cool, I was getting about 49 mpg. Later in the day when it warmed up I climbed to 55 mpg. This was repeated on the way back.

I have a K&N air filter and SE II Slip-Ons, everything else is stock.

My theory is that the ECM was not updated when the filter and pipes were added. I bought the bike used and do not know how to get in touch with the guy that made all the improvements (long story).

Am I on the right path here?

Fat Tony

[csoday]

If the flash was not done, you would know by the popping on decelleration and the bike running hot. A dealer can tell you if it has been flashed.

[hdmarsh77]

I might have been as simple as going against the wind and going with it. Even a few MPH difference can make a difference in MPG.

[Mtclassic]

55mpg, what was your speed? Even 49mpg seems really good.

[fattony]

There is some popping on decel but only at high rev

The way down was there was no wind, fog actually
Speed was pretty steady at 70mph +/-2

On really cold day, high 20s low 30s, the bike smells like its running rich.

FT

[tlewis]

Originally Posted by fattony

On really cold day, high 20s low 30s, the bike smells like its running rich.

FT

Smells rich but sounds lean to me.

[SteveB]

fattony, those seem like good mileage numbers for a big twin . What model do you ride?

[fattony]

2003 FLSTF/I Fatboy
K&N
SE Slip Ons
A real chrome pony

[GrayRider]

41 mpg is the best I've ever gotten.

[SteveB]

Best I've gotten is 52mpg. 206FXDLI

[ratrider]

I may be way off here but I will venture a guess. I run a carb bike so I pay no attention to how injection systems work. Cooler air is denser so it contains more O2. Don't the injection systems measure O2 and add fuel accordingly? I thought they would compensate to some degree for elevation changes as well as air density changes?

I can get over 50 mpg if I am reasonable with the throttle.

[SteveB]

Originally Posted by ratrider

I may be way off here but I will venture a guess. I run a carb bike so I pay no attention to how injection systems work. Cooler air is denser so it contains more O2. Don't the injection systems measure O2 and add fuel accordingly? I thought they would compensate to some degree for elevation changes as well as air density changes?

I can get over 50 mpg if I am reasonable with the throttle.

Currently, only the 2006 Dyna models have O2 sensors.

[GrayGlider]

Originally Posted by ratrider

I may be way off here but I will venture a guess. I run a carb bike so I pay no attention to how injection systems work. Cooler air is denser so it contains more O2. Don't the injection systems measure O2 and add fuel accordingly? I thought they would compensate to some degree for elevation changes as well as air density changes?

I can get over 50 mpg if I am reasonable with the throttle.

I think it's actually the intake air temperatiure sensor that makes this change.
Cooler = denser = feed more fuel

[newultraclassic]

Originally Posted by fattony

I have a theory.....

Just made a run to Ashville, and had a chance to take a good look at my fuel economy.

What I found is that in the morning, when it was cool, I was getting about 49 mpg. Later in the day when it warmed up I climbed to 55 mpg. This was repeated on the way back.

I have a K&N air filter and SE II Slip-Ons, everything else is stock.

My theory is that the ECM was not updated when the filter and pipes were added. I bought the bike used and do not know how to get in touch with the guy that made all the improvements (long story).

Am I on the right path here?

Fat Tony

You think 49 mpg is bad? That's more than 99% of Harleys get. Don't worry, be happy.


.

[fattony]

Thanks Everyone

This is me not worrying, and being happy

Fat Tony