Fuel Light

Discussion in 'Engine, Fuel and Exhaust' started by ZombieOutlaw, Sep 12, 2016.

  1. ZombieOutlaw

    ZombieOutlaw New Member

    2008 XL1200C 4.5 Gal gas tank. I get to around 130 miles on the trip meter and the fuel light comes on. I go and fill up and put in 2.5 gallons. (EDIT) Is there some gas hidden in one of the tires or a saddle bag that the fuel sensor is not picking up? I'm afraid of not filling up because who knows how far you can go on a tank full. Common sense would tell me that I should have about another 85 miles of fuel left but who knows. I just don't want to end up dry on the side of the road. Any ideas about this fuel sensor or expected miles per tank would be greatly appreciated. My last bike had a reserve toggle so I never had this issue before.

    Last edited by a moderator: Sep 12, 2016
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    Strap a gallon jug of fuel on the bike somewhere and run it all the way out of gas riding the way you usually do (all highway, all surface or a mix like you do normally). Keep track of how many miles that was from the last fill up. Subtract 20 miles from that number and that should be the "gotta get some gas" mileage on the trip odometer.

    The other solution is to figure out how the bike measures the fuel in the tank and see what it takes to re-calibrate that. Sometimes easier just to keep an eye on the trip miles and get used to using that as your trigger.


  3. RibEye

    RibEye Junior Member

    Fuel sending unit float rod possibly bent during previous work. Check that and see if you are getting full range of motion, and where.

    Rich P
  4. roadking96

    roadking96 Member

    My 2014 XL1200C is the same way since brand new. For that matter so is my 96 Road King. I keep track of the mileage though and I don't like to run my fuel level low, especially when it's hot out. It can be done but I try not to make a habit out of it. Unlike an automotive electric fuel pump that sits in a nice cool place toward the rear of the vehicle, my bikes pumps sit right above the engine and get warm so I like to keep them submersed in fuel as much as I can. I usually ride about 100 to 120 miles with either bike and fill up again. I can't go wrong and I feel no need to be running on fumes looking for a gas station, although I used to do it all the time especially when I had a Sporty with a peanut tank. I could reach in and tweak the float level on the King but I don't want to break that 20 year old seal.
  5. Jack Klarich

    Jack Klarich Guest

    [​IMG] # 10 is the fuel level sensor, Bad ?
  6. roadking96

    roadking96 Member

    It's a great question - If you do a search for it there are many Sportster owners on their 3rd sensor, in fact some of the owners posted on this forum, though it's been awhile. Sounds like sometimes the light would come on and stay on during some weird conditions. I would be curious to know if any Sportster owners bought the Fuel Gauge Kit Part Number 75031-09 and How that works. The installation document near as I can tell says to use the original sensor. In any event looking at the service manual there appears to be a 3 wire resistor assembly in that circuit that shares a common ground labeled Grnd 1. This is the ground for the level sensor. It can be found in the 2014 Sportster service manual Fig B9 Main Harness 1 of 2. It would be really helpful if some one had a spec or some information on how the sensor circuit works. The two resistors in the assembly are 8K ohms and 2K ohms. This doesn't mean it is not the sensor but it will cost about 80 bucks to find out. This link is about the best information I've found so far and it has some good pics too. Page 3 is where its at- good luck and good discussion. Maybe we will figure something out.
  7. Jack Klarich

    Jack Klarich Guest

    My fuel light comes on with 1 gallon left spot on, my 15 came on with 1.6 gallons left
    My speedo is off by 3mph clocked yesterday @ f5mph it reads 78mph