Kyosho IH108 Shock Cap Set Mini Inferno ST

This is the shock cap set for the Kyosho Mini Inferno ST.

The cap closes the top of the shock body and, with the diaphragm beneath it, is what actually seals the damper. That makes it more important than a simple lid. If the cap does not seat and seal properly, the shock either loses oil past the joint or draws air in, and air in the oil foams it and progressively kills damping through a run. The car just gets worse lap by lap and nothing looks broken.

Caps also carry the thread that the shock body screws into, and that thread is the part that suffers. Cross-threading during a rebuild, or simply repeated assembly cycles, wears it until the cap will no longer torque down evenly. A cap that will not seal is not repairable, so replacing it is the fix.

Fresh caps are worth fitting whenever you are rebuilding shocks properly rather than reusing tired ones. Fitment covers the Mini Inferno ST and Mini Inferno ST 09 including the ReadySet and ARR versions. Note that Kyosho lists this part as discontinued.