CNC machined plastic washers, in both 5mm & 2.5mm thicknesses, are a straight fit with the OEM Yamaha Fork Caps, and can give up to a maximum of 12.5mm preload on each of the OEM fork springs.
Eack kit consists of:
4 x 5mm thick washers
2 x 2.5mm thick washers.
Alternative fitting solution (without removing forks and wheel): FITTING VIDEO LINK