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[kng103]

what is the correct air fuel ratio supposed to be?

[hd-dude]

13.8

[kng103]

13.8

thanks.
i did a search and found some post that say 13.5
who came up with the number?

[hd-dude]

More info.....

For maximum power, the proper air/fuel ratio for normal engine operation is between 13:1 and  14:1. This is slightly rich and is not the "stoichiometric" ratio 14.7:1 (ideal chemical mix). The "ideal chemical mix" does not produce max power in most engines. The ratio simply means that every 1 part of gas requires 13 or 14 parts of air for optimal combustion. More than 14 parts of air results in lean mixtures and less than 14 parts of air results in rich mixtures.

[kng103]

More info.....

For maximum power, the proper air/fuel ratio for normal engine operation is between 13:1 and  14:1. This is slightly rich and is not the "stoichiometric" ratio 14.7:1 (ideal chemical mix). The "ideal chemical mix" does not produce max power in most engines. The ratio simply means that every 1 part of gas requires 13 or 14 parts of air for optimal combustion. More than 14 parts of air results in lean mixtures and less than 14 parts of air results in rich mixtures.

thanks again
the main reason for my question is that i noticed that some of the members on the site have had each cylinder tuned seperately.
so, saturday weather permitting, i am going to have the bike retuned for about the 100th time.

[hd-dude]

Kng;

As far as tuning each cylinder I would definitely recommend that the tuner take the time to do that. When I had mine done a couple of weeks ago Bob (the tuner) did a run after he was done with the front cylinder to show me where it was. When he did the initial pull with the sniffer in the rear pipe the AF was all over the place. I do not remember exact numbers but I think it was a 3-5 HP and TQ gain after he was done with the rear.

[HUBBARD]

what is the correct air fuel ratio supposed to be?

When it's blowin' Black Smoke out the RINEHART's @ 6000 RPM's. [smiley=huepfenlol2.gif]  There endeth the lesson.  Later--HUBBARD  

[grc]

what is the correct air fuel ratio supposed to be?

Most Harley tuners seem to shoot for somewhere in the 13.2 to 13.8 range, with 13.5 being the average, at wide-open-throttle.  The richer numbers are safer, but the leaner ones will give more max power (hotter equals more pressure pushing those pistons down, and too rich runs cooler).

Jerry

[kng103]

When it's blowin' Black Smoke out the RINEHART's @ 6000 RPM's. [smiley=huepfenlol2.gif]  There endeth the lesson.  Later--HUBBARD  

thanks for the intelligent reply hub.
how do you like your johnny cakes?

[475wildey]

When it's blowin' Black Smoke out the RINEHART's @ 6000 RPM's. [smiley=huepfenlol2.gif]  There endeth the lesson.  Later--HUBBARD  

When its blowin blue smoke from the rear tire...
There endeth the lesson

sorry for the copyright infringement there hubb just had to say it... [smiley=cool26.gif]

[DavidB]

When it's blowin' Black Smoke out the RINEHART's @ 6000 RPM's. [smiley=huepfenlol2.gif]  There endeth the lesson.  Later--HUBBARD  

Same way I did the Shovel and Pan Head.
They always ran like a charm.

[HUBBARD]

When its blowin blue smoke from the rear tire...
There endeth the lesson

sorry for the copyright infringement there hubb just had to say it... [smiley=cool26.gif]

No problem there, 475wildey.  Glad I could help!  [smiley=huepfenlol2.gif] Later--HUBBARD

[HUBBARD]

Same way I did the Shovel and Pan Head.
They always ran like a charm.

Where you been there, Bro' Dave?  Glad to see you back!  Nothin' sounds like a cheated up Shovel with 2" Drag Pipes!  Did I just hear you say, "Man, ain't that the damn truth!"  [smiley=xyxthumbs.gif] Later--HUBBARD

[soups7]

Factory settings are supposedly very lean, does anyone know what they are?

My '03 SERK is currently at 13.5 and my dyno guy said they had trouble getting the sniffer into the back pipe of my thunderheader to properly do the rear cyl.
Just had the 50MM Zippers TB with their HUGE ac added, not impressed yet but still working omn it. Any suggestions?

[kng103]

Factory settings are supposedly very lean, does anyone know what they are?

My '03 SERK is currently at 13.5 and my dyno guy said they had trouble getting the sniffer into the back pipe of my thunderheader to properly do the rear cyl.
Just had the 50MM Zippers TB with their HUGE ac added, not impressed yet but still working omn it. Any suggestions?

I don't think you can tune each cylinder with a 2 into 1 pipe.