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Old Mar 6, 2016 | 05:48 PM
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Default Terrible MPG
Getting about 27 MPG on my 83 FLH with S&S carb.
Carb has been cleaned and rebuilt (my me).
Plugs kinds sooty so went leaner on jetting.
Slight backfire on deceleration now - so I think it is close.
Is this the normal mileage for the old shovel engine?
 
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Old Mar 6, 2016 | 05:53 PM
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Seems on the low side.
My '69 FLH with a Bendix carb consistently gets in the 33-35 MPG range.
 
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Old Mar 6, 2016 | 06:00 PM
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Bit low which carb you have an older " B " or the shorter " E " , B's got around 35 average and the E's should roll the low 40's depending a few things and your tune.

Hit S&S's website and read the E setup & tuning guide it's free and easy to follow.
 
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Old Mar 6, 2016 | 07:47 PM
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LMAO
I knew it was gonna be an S&S Carb...
Everyone always tunes 'em Fat!!!
 
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Old Mar 6, 2016 | 08:23 PM
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Originally Posted by Racepres
LMAO
I knew it was gonna be an S&S Carb...
Everyone always tunes 'em Fat!!!
That's because most guys are tuning around the intakes leaks they never fix.
 
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Old Mar 6, 2016 | 11:06 PM
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Very true, but, even without leaks, most run it too rich...they do work better that way, Unless you know how to Properly tune a Thunderjet equipped one.
 
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Old Mar 6, 2016 | 11:29 PM
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Yeah they do like a hair fat on a shovel.
 
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Old Mar 7, 2016 | 07:01 AM
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Originally Posted by TwiZted Biker
Bit low which carb you have an older " B " or the shorter " E " , B's got around 35 average and the E's should roll the low 40's depending a few things and your tune.

Hit S&S's website and read the E setup & tuning guide it's free and easy to follow.
It is the "E" version. I will check the website for tuning tips. Thanks.
My indie mechanic has a dyno and seems to know how to tune older iron, so that may be another (expensive) option.

Also wondering if there is some other components (not just the carb) that could cause this. Valves? Timing? Ignition?
 
Last edited by LostInNM; Mar 7, 2016 at 08:14 AM.
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Old Mar 7, 2016 | 10:59 AM
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Like TwiZted has said
Intake leaks are the Number one problem
Masked by tuning very Rich
 
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Old Mar 7, 2016 | 12:00 PM
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Originally Posted by LostInNM
Getting about 27 MPG on my 83 FLH with S&S carb.
Carb has been cleaned and rebuilt (my me).
Plugs kinds sooty so went leaner on jetting.
Slight backfire on deceleration now - so I think it is close.
Is this the normal mileage for the old shovel engine?
You runnin drag pipes by chance?
 
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