How to Service Your Own Harley Fatboy

Written by chris gilliland Google
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How to Service Your Own Harley Fatboy
(Justin Sullivan/Getty Images News/Getty Images)

As with any machine, a Harley-Davidson Fatboy requires a strict maintenance schedule to keep it top-running condition at all times. The cost associated with these regular maintenance intervals are often quite high, leaving many Fatboy owners searching for other alternatives. Undertaking a majority of the service details yourself offers such an option, saving you some cash while providing a deeper understanding of your motorcycle's operation. For the most part, the basic procedures are fairly straightforward and can be performed using standard mechanics tools. Keep in mind that some tasks, including motor and transmission repair, are best left to the professionals.

Skill level:

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Things you need

  • Socket wrench
  • Sockets
  • Multimeter
  • Automatic battery charger
  • Light bulbs
  • Service stand
  • Flat screwdriver
  • Oil pan
  • Filter wrench
  • Oil filter
  • 3 qts. 20W50 motor oil
  • 1 qt. Harley-Davidson transmission fluid
  • Torx screwdriver
  • 1 qt. Harley-Davidson primary fluid

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    Battery, Lights and Charging System Inspection

  1. 1

    Unscrew the nut from the back of the motorcycle's seat, using a socket wrench. Lift the seat off of the frame to access the battery.

  2. 2

    Test the battery's current charge, using a multimeter set to test a DC (Direct Current) voltage scale. Place the multimeter's red probe on the battery's positive (+) terminal, then the black lead on the battery's negative (-) terminal. Charge the battery with an automatic battery charger if the voltage reading is less than 12.1 volts DC.

  3. 3

    Start the motor and open the throttle to raise the engine speed to 3,000rpm (revolutions per minute). Take another voltage reading at the battery, using a multimeter. Contact your local Harley-Davidson dealer to troubleshoot the charging system, if the battery's charging voltage is less than 14.1 volts. Close the throttle and allow the motor to idle.

  4. 4

    Activate the headlight, indicators and brake light to ensure that all lights operate properly. Replace any bulbs that do not illuminate.

  5. 5

    Stop the motor. Reinstall the seat, using a socket wrench to tighten the nut on the rear of the seat.

    Fluid and Filter Replacement

  1. 1

    Lift the motorcycle into a vertical position, using a service stand.

  2. 2

    Unscrew the oil tank drain hose's clamp, using a flat screwdriver. Pull the drain hose off of the left side of the frame, behind the motor, and drain the motor oil into an oil pan. Push the drain hose back onto its mounting stud on the frame, use a flat screwdriver to tighten the hose clamp.

  3. 3

    Unscrew the oil filter from the front of the motor's crankcase, using a strap wrench. Fill the new oil filter with .25 qt. of 20W50 motor oil. Screw the oil filter onto the crankcase by hand, stopping once the filter's gasket is touching the motor. Tighten the filter by an additional half turn by hand.

  4. 4

    Unscrew the cap from the right side of the oil tank. Pour 2.75 qts. of 20W50 motor oil into the oil tank. Screw the cap back onto the oil tank.

  5. 5

    Unscrew the drain bolt from the bottom of the transmission unit, using a socket wrench. Drain the transmissions fluid into an oil pan. Screw the drain bolt into place, using a socket wrench.

  6. 6

    Remove the cap from the right side of the transmission unit. Pour 1 qt. of Harley-Davidson transmission fluid into the transmission unit. Screw the cap back onto the transmission.

  7. 7

    Unscrew the drain bolt from the primary housing on the left side of the motorcycle, located just below the primary's round clutch inspection cover, using a Torx screwdriver. Drain the primary fluid into an oil pan. Screw the drain plug into place, using a Torx screwdriver.

  8. 8

    Remove the clutch inspection cover, using a Torx screwdriver to remove the cover's bolts. Pour 1 qt. of Harley-Davidson primary fluid into the primary through the clutch inspection port. Stop filling once the primary fluid is level with the bottom of the clutch assembly within the primary.

  9. 9

    Reinstall the clutch inspection cover onto the primary, using a Torx screwdriver to tighten the cover's bolts.

Tips and warnings

  • Purchase a Harley-Davidson service manual for detailed instructions and additional servicing procedures.
  • Know your limits. Have the work performed by a Harley-Davidson technician if you feel the job is beyond your skill level.

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