The YSS fork upgrade kit contains a narrower fork spring, a fork valve and an adjustable fork stem block.
The fork valve changes the flow of oil into the fork in both directions and the fork spring causes tighter spring behavior.
With the handlebar cover it is possible to re-adjust the spring preload of the fork: turning the adjustment screw increases the pressure and therefore the preload of the fork spring.
YSS supplies this vehicle specific kit as a whole set.

Attention: it is essential to follow the assembly instructions in the attached PDF