A casing on the backside of the engine houses the Harley-Davidson (H-D) Sportster transmission. The primary chaincase holds the lubricant shared with the clutch components and the primary drive chain. Normal vehicle service includes changing the lubricant, and should be performed at 1,600 km (1,000 miles) and at each 16,000 km (10,000 mile) service after that.
Ride the bike until the engine reaches full operating temperature. Park the bike on firm, level ground.
Cover the rear master cylinder with a workshop rag. Grasp the left side-cover and pull it away from the plastic mounting clips on the frame.
Compress the locking tabs on the main fuse by hand. Pull the main fuse connector off the fuse terminals.
Raise the bike off the jiffy stand to the vertical position. Hold it for three minutes to allow the oil to settle in all of the passages before proceeding. Get someone to keep hold of the bike up throughout the rest of the process.
Remove the left rider footrest bolts from the frame with a ratchet and Allen key. Remove the footrest from the bike.
Remove the six clutch inspection cover mounting screws with a ratchet and Allen key. Pull the cover from its recess, and inspect the rubber seal for damage or wear. Replace if necessary.
Pour the H-D lubricant into the clutch inspection hole until the fluid level reaches the bottom edge of the clutch diaphragm spring.
Install the clutch inspection cover screws. Torque the screws to between 9.5 and 12 Nm (84 and 108 inch-pounds), using a 6 mm (1/4 inch) torque wrench.
Install the rider footrest and mounting bolts. Torque the bolts to between 61 and 68 Nm (45 and 50 foot-pounds), using a 9 mm (3/8 inch) torque wrench and Allen key.
Push the main fuse connector onto the fuse terminal until the locking tabs snap into position. Position the left side-panel and snap it into the plastic mounting tabs in the frame by hand.