I have a 1998 Fatboy and when I hit 118 miles I ran out of gas completely. The tank is stock 4.2 gallon.

With that my MPG was 28.

My plan is to order a 6 gallon tank and rebuild my carb.

If I keep the same MPG then I will have no problem getting the 120 to 130 mark then will have gas left over when I stop for gas.

Should I do basic rebuild or should I do master rebuild or what else should I look for?

 

 

Well it did sit for a year I bought it from a dealership then took it home after it sat.

I am gonna change the plugs and wires and tune it up along with rebuilding the carb and the bigger tank.

 

1. You should be getting 120-130 miles to the tank now.
2. What makes you think you need a carb rebuild? Is the butterfly loose and sloppy? Is the carb leaking?
3. Before you do ANYTHING watch the first video and perform all the steps. Then watch the second video and do that if necessary,.
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Super E carbs are almost bulletproof and will run for years with little if any problems.

 

something is amiss!
i can run my 1200s with 3.3gal to the 120 range easy without reserve, but that is sane. if i baby it, about 60mpg and twisting it very low 30's. i run int'l gearing so IF i stay below 3k rpm, all is good but if i let the 200 main kick in, not so good. at 3k i am running 70mph and at 5k, nothing left for the speedo to measure with 2.5k left to go. i am not stock and the tranny is mod'd too.
the first thing i would be doing is compression/leak down as low compression = low power output = more throttle.

 

Wow .. A super E with a 200 main? You have to be running Nitro. And you get 60MPG?

 

Hey Bustert,
why don't you bring your sportster down here to sunny florida and see if you can keep up with mine, I only run a 66 main jet in my S&S Super E.
m

 

Now back to the OP. what pipes are you running? and what jets are installed in your carb. You might get much better results by just getting your carb jetting correctly dialed in. remove your floatbowl and record what jets you have installed and post back up the info, then we can help more.
m

 

Pull the bowl and check your jets, something doesn't sound right there... I seen the worst builds even big inch Evo motors get better mileage in that.. I'm sure somebody put the wrong jets in it..... Unless your running with the enricher on...

 

If the carb ain't leaking about the only thing you need to possible replace is the bowl gasket. Poor fuel mileage can be caused by more than one thing.. If compression is good and ignition timing correct and you are not running open drag pipes, you can look into the carb.. As already stated make sure the enrichener is closing all the way, Look at how much accelerator pump is add. Many new carbs have it set wide open. Your intermediate jet should be something like a 28 or 29.5. Main mid to high 60s. If you have a different air-cleaner, check to make sure the bowl vent is clear. Also make sure the float level is set correctly and the O ring on the top of the accelerator pump tube is in place.