Low MPG normal?
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Stage III
Joined: May 2011
Posts: 3
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From: Menifee CA
Low MPG normal?
My bike is a 2000 FLSTF and has the v&h drag pipes and s&s carb. Not that I care, because i didnt get it for its gas efficiency but it only gets about 25 mpg. Im usually driving on the freeway going 80, not sure if it affects it, but is this normal? My bike did sound kind of funny, occasional back fire and sputtered a little. So i went to the S&S website and they instructions on how to bring the carb back to factory default settings. The only thing is it says to put the idle speed screw all the way to seated and back it out 1.5 turns. Then you are suppose to warm up the bike. well when the screw is that far in and you turn the bike on it immediately goes straight to up to redline. Scared the **** out of me, so i put it back to what it was. Then i just messed with the idle mixture screw and followed the instructions. It sounds better now. Going to ride it this week a little more to see if it preforms better. Just wondering if you had any ideas. This is my first bike and would like to learn how to do as much as I can my self. I changed the oils/filter when I bought it in March and added a K&N air filter today.
Former Sponsor
Joined: Jan 2009
Posts: 19,364
Likes: 40
From: Los Angeles, CA
25 on the freeway seems really low to me. It must be running extremely rich. I avhe a 95" kit, cams, custome Dyno tune with a power commander and I get 40 mpg on the highway at 90mph. Most likely your jet or jets are too large.
Drew
Drew
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Stage III
Joined: May 2011
Posts: 3
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From: Menifee CA
Any suggestions, should I replace the jet with a smaller one? Should I just give in and take it to harley or motorcycle shop for a tune up? How do I know what size jet I have? I did notice is its spraying a decent amount of fuel, although I have no idea how much should spray out.
Road Master
Joined: Aug 2007
Posts: 1,049
Likes: 5
From: Emerald Coast, FL
Sounds as if your bike was set up to race from stoplight to stoplight around town. First off the drag pipes do not give you enough back pressure to optimize engine performance over 45mph... I would recommend adding wrapped baffles... you still get the good sound as well as the correct back pressure. You are on the right track about carb jets... the idle jet should be 2 to 3 turns out at peak performance. Also, by what you are describing, the rest of the jetting is for drag performance... my advice, have a good indy do a tune to your riding habits or if you want to get into it yourself buy a jet pack and start fooling around... you can't really hurt anything. Start with a 45 or sportster jet and work from there. My bike has a thumb idle screw for ease in fine tuning the "potato" sound into it.,. the rest of the jets are factory but set for optimum power and performance... Dyno results = 76 hp and 147 max mph... also get between 38-42 mpg at 80-85 mph.
Road Warrior
Joined: Dec 2010
Posts: 1,268
Likes: 507
From: Florida
If you turned your idle speed screw in till seated you screwed the pooch, and it would have runaway at start up. You were to turn in the idle mixture screw till lightly seated then back it out the one and a half turns. S&S jets are stamped as to what size they are. Read further on their site and there is a chart for approxamate jet sizes.
Last edited by V-Twins & Bowties; May 2, 2011 at 08:10 AM.
Club Member
Joined: May 2007
Posts: 145,895
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From: 40 miles Northeast of Indy..
If you turned your idle speed screw in till seated you screwed the pooch, and it would have runaway at start up. You were to turn in the idle mixture screw till lightly seated then back it out the one and a half turns. S&S jets are stamped as to what size they are. Read further on their site and there is a chart for approxamate jet sizes.
I understood thats what he did.. he just didn't say how much further out his was to start with.
haven't had a carbed bike for yrs, just have to get the right jets for Ur set up..
And yes 25mpg is really poor, 38-45 is normal.
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Stage III
Joined: May 2011
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From: Menifee CA
So I pulled out the jets and the main is 72 and the intermediate is 295. is the smaller the number the bigger the hole? The idle speed screw is out 5 turns the idle mixture I turned till the bike started to die and then backed it off till it sounded better. All three screws are in the 4-5 turn range. I checked the S&S jetting guide and according to that, the ranges for and 86" are .030 to .033 and .072 to .082 on the main. Are these stock jets? If so, does that mean something else is causing poor mileage? Should i go down a few sizes maybe, even though its not in the range?
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