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curvelover

Brooklyn, New York

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Posted: 03/05/08 10:44am Link  |  Quote  |  Print  |  Notify Moderator

I have a new 08 Roadking.To cool it down a bit and to get a little more noise, I had a SE air filter, V&H slipons and a HD racetuner installed. I am happy with the upgrades, but I am now getting 24-25 miles to the gallon. Down from 43-44 mpg. I put alot of miles on the bike so this is a big concern. Is there anything I can do about this? Any ideas or suggestions would be greatly appreciated

King of the Road

Union County, NJ

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Posted: 03/05/08 02:10pm Link  |  Quote  |  Print  |  Notify Moderator

Was the bike dynoed after the installs? That might help. Unfortunately the lean condition and the high heat go hand in hand. Better airflow through the engine requires more fuel to keep the stoichiometry in the proper range. This is accompanied by the increase in hp/torque usually.

Hawg Man

Lakeland, FL

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Posted: 03/05/08 03:01pm Link  |  Quote  |  Print  |  Notify Moderator

King of the Road wrote:

Was the bike dynoed after the installs? That might help. Unfortunately the lean condition and the high heat go hand in hand. Better airflow through the engine requires more fuel to keep the stoichiometry in the proper range. This is accompanied by the increase in hp/torque usually.


I agree with King of the Road - but only to a point.

If the gas mileage has dropped nearly 50%, then that would mean the amount of fuel going through the engine has INCREASED by roughly 50%.
Right?
Would that then mean the engine is ingesting and moving 50% more air?
And would it then follow that it's making 50% more horsepower?
I seriously doubt either one applies.
Have someone ride close behind you and see if they can smell what appears to be an over-rich exhaust.
I won't attempt a guess at exactly what the problem is, but that much of a difference in mpg tells me there's something else going on.
Have you pulled the plugs to look at the color?

My '05 Road King has a Stage 1 Kit, SE slip on mufflers and a True Dual kit.
I get 45-46 mpg.
It USED to run hot with the Stage 1 and SEs - but it has cooled down significantly since installing the True Duals, even though the True Duals don't seem to have made a measureable difference in the mpg.


"$15,000, a new leather jacket, and 15 miles under your butt doesn't make you a biker."


Tommy Tune

Newark, De. 19713

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Posted: 03/05/08 04:10pm Link  |  Quote  |  Print  |  Notify Moderator

I dunno. I did a 95 inch kit with high performance cams and I'm getting better mileage than that. I probably get between 30 and 35 MPG.


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King of the Road

Union County, NJ

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Posted: 03/05/08 09:11pm Link  |  Quote  |  Print  |  Notify Moderator

I agree, the a/f ratio is out of whack. Wonder if they just slapped the racetuner on without any setup? Just pull in front of someone on the road and look in the rear view. If they're wiping their eyes and coughing up a lung, you might be running rich.

Hawg Man

Lakeland, FL

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Posted: 03/06/08 07:57am Link  |  Quote  |  Print  |  Notify Moderator

King of the Road wrote:

I agree, the a/f ratio is out of whack. Wonder if they just slapped the racetuner on without any setup? Just pull in front of someone on the road and look in the rear view. If they're wiping their eyes and coughing up a lung, you might be running rich.


LOL

Kinda reminds me of back in the day when we had a couple guys with 3-cylinder, 2-stroke Kawasakis that rode with our group.

We ALWAYS made them ride in the rear.
Otherwise - we would all get so much oil covering our glasses we couldn't see after about 2 or 3 miles.
True story.

curvelover

Brooklyn, New York

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Posted: 03/06/08 05:37pm Link  |  Quote  |  Print  |  Notify Moderator

thanks for the replies. I brought it back to the dealer that dyno'd it. He pulled up the dyno sheet and showed me a flat air/fuel line that he said was perfect. He said a change to a less free flowing muffler would help and then he would lean out the air/fuel mixture on another dyno. That would help the milage at the expense of power and an increase in heat. hopefully there is some happy medium. Any suggestions on a less free flowing muffler than the screaming eagle muffler

Thanks again guys

curvelover

Brooklyn, New York

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Posted: 03/06/08 05:39pm Link  |  Quote  |  Print  |  Notify Moderator

PS The sparkplugs were clean so I don't think it was running rich.

rr1985

Centeral Alabama

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Posted: 03/07/08 02:46pm Link  |  Quote  |  Print  |  Notify Moderator

A friend I ride with has the Rineheart slip on mufflers on his 06 Road King, The sound is deeper not to loud. I have the V&H slip on muffler on my 07 Softtail. a good pipe for the money but if I was puting the mufflers on today the Reinheart is the way I would go.

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