Motorcycle Fork Compression Free Piston Inner Shaft Seals

If your motorbike has modern "Separate Function Forks", you probably have a comp adjustment clicker on one top cap & reb on the other, but for many adjustable designs both caps have compression damping adjusters - learn more about open or closed chamber front forks. If you've never adjusted your dampers, read our clickers article - they're like opening or closing a tap for more or less suspension oil to flow.

Adjuster assemblies are compact but complex, everything revolving around a threaded hollow centre rod.

A free piston slides up & down it, with outer o-rings & bushes to seal against the fork tube. For the inside of the floating piston, there are these genuine factory KYB & Showa suspension shaft seals, to prevent oil getting past - or gas in the case of pneumatic forks.

A cover cap is screwed onto the top of the centre shaft, sealed against the upper fork tube with an o-ring, with clicker assembly & bleed screw inside. An Inner Chamber Spring presses between the top cap & this sliding piston - helping set the initial fork plushness - so changing how strong the ICS is will make the forks feel softer or firmer at the beginning of the stroke.

At the bottom end of the shaft are the comp valving piston parts - a specific set of shims & washers assembled either side of a piston and locked onto a base valve "tower" with a locknut. A pushrod slides inside it all, pressing harder or softer on the valves depending on your clicker adjustments, compressing or loosening the stack.

If you can't find what you are after, we have a collection of small clicker parts in our Fork Adjuster Parts category - plus we have some great aftermarket parts for comp assemblies like clicker knobs and super strong billet alloy free pistons. For people looking to tune beyond the OEM valving we carry revalving kits to push your performance to the next level!