[SpudRider]

The locking ring for the shock spring has a single Allen bolt which tightens it. You adjust the spring preload either by turning the spring itself, or by turning the locking ring, which sits above the spring at the top of the shock. You don't need a special tool to tighten the spring preload. To gain access to the locking ring and the Allen bolt, remove the battery and the battery box from the motorcycle.

First, remove the battery. Then remove the evaporative canister which is attached to the bottom of the battery box.