There was a time when the Sportster was considered the black sheep of Harley-Davidson's motorcycle lineup. The Sportster's bad boy image was based on Harley's K-series machines that were the brand's epitome of performance in the 50s and 60s. Fast-forward to the year 2004 and the Sportster's bad attitude has been refined while retaining the classic flair of the earlier K-bikes. The bike's twin rear shock absorbers are examples of traditional motorcycle design. While not as technologically advanced as a high-performance monoshock setup, the twin shocks work well on most roads. Additionally, they offer enough adjustment to compensate for the added load of riding with a passenger.
Things You'll Need
- Tape measure
- Hook-type spanner wrench
Straddle the motorcycle and lift it up and off of its side stand. Have an assistant measure the rear shock absorber sag -- the distance between the rear fender and the top of the swingarm -- using a tape measure.
Sit down on the motorcycle to compress the rear shock absorbers. Measure the distance between the fender and the swingarm again. Ideally, the distance should only have reduced by one inch. If the change is less than one inch, the shock absorber spring preload is set too firm. Alternatively, if the change is greater than one inch, the spring preload is set too soft.
Lower the motorcycle onto its side stand. Look at the cam adjuster ring at the bottom of each rear shock absorber, directly below the spring. The adjuster ring will have five stepped settings, indicating how much preset tension is being placed on the spring. The smallest ramp is the shock absorber's softest setting, while the tallest ramp -- closest to the bottom of the shock -- denotes the firmest setting.
Turn the left rear shock absorber cam adjustment ring clockwise one ramped step at a time, using a hook-type spanner wrench, to increase the spring preload. Turn the adjustment ring counterclockwise to decrease. Turn the right shock absorber adjustment ring to the identical setting. Recheck the rear shock absorber sag and make further adjustments until the change between the compressed and uncompressed sag is at or near one inch.
Take the motorcycle out for a test ride. If the rear fender bottoms out -- touches the rear wheel -- during the ride, increase the spring preload by one step.
Tips & Warnings
- If you frequently ride two-up -- riding with a passenger -- you will want to increase spring preload to adjust for the additional weight. Sag measurements should be taken with both you and your rider, so you can adjust the shock absorbers accordingly.
- 2004 Harley-Davidson Service Manual: Sportster Models; Harley-Davidson Motor Company; 2004