Primary Chain Inspection
Primary chain free play should be inspected at proper intervals and adjusted as necessary. If the chain is allowed to run loose, it will cause the motorcycle to jerk when running at low speed, and chain and sprockets will wear excessively. If this happens, see a Harley-Davidson dealer.
WARNING
To prevent accidental vehicle start-up, which could cause death or serious injury, remove main fuse before proceeding. (00251b)
  1. Remove main fuse. See Maintenance and Lubrication → Fuses and Relays.
  2. See Figure 1. Remove the two hex socket screws and the primary chain inspection cover (1).
  1. See Figure 2. Check primary chain tension by measuring free play.
    1. Measure free play through chain inspection cover opening.
    2. Rotate engine to move primary chain to a different position on sprockets.
    3. Measure free play several times, each time with primary chain moved so that the measurement is taken with sprockets rotated to the tightest chain position.
  2. The tightest measurement in previous step must be within the specifications. Adjust as necessary. Refer to Table 1.
Figure 1. Primary Chain Free Play
1Locknut
2Chain adjuster screw
3Transmission chaincase drain plug
Figure 2. Primary Chain Adjuster: Sportster Models
Table 1. Primary Chain Free Play Specifications
ENGINE
in
mm
Cold
3/8-1/2
9.5-12.7
Hot
1/4-3/8
6.3-9.5
Primary Chain Adjustment
NOTICE
Do not adjust the primary chain tighter than specified. Running chain too tight will result in excessive wear. (00202a)
1. See Figure 1. Loosen locknut (2).
2. Turn chain adjuster screw (3) clockwise (inward) to reduce free play or counterclockwise (outward) to increase free play. Free play must fall within specifications. Refer to Table 1.
NOTE
If free play cannot be set within specification, then primary chain and/or chain adjuster are worn beyond adjustment limits. See your Harley-Davidson dealer.
3. When free play is set correctly, hold chain adjusting screw and tighten locknut to 27–34 N·m (20–25 ft-lbs).
4. Install primary chain inspection cover with a new gasket. Tighten hex socket screws to 10.2–13.6 N·m (90–120 in-lbs).
5. Install main fuse.