Yokomo YOKYS8D Diaphragm Shock Cap Set for Yokomo/Associated, damper part for RC suspension tuning  [YOKYS8D]

Diaphragm shock cap overview

This diaphragm shock cap set is an RC-scale damper component intended for use on Yokomo and Associated shock bodies. The parts replace the conventional solid cap with a flexible diaphragm element that helps maintain internal pressure, reduce oil aeration, and stabilise damping behavior during repeated compressions.

Compatibility is limited to the brands listed in the product name, consult your shock body design before replacing caps. The diaphragm works by isolating the oil from direct exposure to air inside the shock, which reduces foam and maintains consistent damping over a run.

Installation is straightforward for a modeller familiar with dampers: remove the shock assembly from the car, drain or contain shock oil as needed, remove the original cap, seat the diaphragm flush against the shock body, and reassemble while checking for proper seating and even tightening to avoid pinching the diaphragm. After assembly, cycle the shock slowly to confirm there are no leaks and that the movement is smooth.

For tuning, use the diaphragm cap to complement spring and oil changes; the cap does not replace standard tuning items but helps preserve oil performance and repeatability, especially in high-frequency tracks or extended runs.