YZ-4SF Slipper Shaft Replacement S4-303MSA Yokomo  [S4-303MSA]

Slipper main shaft suited to YZ-4SF

The S4-303MSA functions as a replacement main shaft for the slipper assembly used on YZ-4SF models. It retains the slipper parts while maintaining the slip action intended to safeguard drivetrain pieces under load.

This spare is listed for chassis code B-YZ4SF; confirm that code on your model before purchase. It is presented as a standard replacement rather than a bespoke upgrade, designed to match original slipper fitment for the YZ-4SF chassis.

Typical installation involves removing part of the slipper unit to extract the old shaft and fit the new one, then checking alignment and engagement of pads or springs during reassembly. Fit this shaft as a direct swap to recover factory slipper alignment and engagement when performing maintenance or adjustments.