O.S. Engine OS22514000 25AX Heatsink Cylinder Head  [OS22514000]

Thermal management head for 25AX

This finned heatsink head serves as a replacement cylinder head for the O.S. Engine 25AX range. Fins expand the cooling surface and aid in drawing heat away from the combustion chamber for steadier temperatures.

Fitting requires basic engine servicing skills: remove the stock head, clean the contact faces thoroughly, decide on a new or reused head gasket depending on condition, and torque the head down evenly. Take care not to overtighten and ensure the head sits flush before final tightening.

In tuning and maintenance, the heatsink head reduces thermal swing, helping to limit temperature-induced drift when adjusting needles or aiming for sustained high RPMs. Keep an eye on the head and sealing surfaces during routine checks.