Yokomo S4-002BRLA Aluminum Rear Bulk Head (Left) for YZ-4S — Aluminum left rear bulk head for YZ-4S chassis  [S4-002BRLA]

Left rear bulk head for YZ-4S

This is a left-side aluminum rear bulk head designed for the Yokomo YZ-4S platform, supplied under model S4-002BRLA. It replaces the original left rear bulk head to provide a stiffer mounting point at the rear of the chassis while maintaining factory mounting geometry.

Compatibility is focused on the YZ-4S series and the listed supported chassis; confirm your chassis code before installation. The part is produced from machined aluminum to improve rigidity and wear resistance compared with standard plastic parts.

In tuning terms, replacing the stock left rear bulk head with a metal unit affects rear-end stiffness and can change how the rear suspension transmits loads into the chassis. Use this part when aiming for more consistent rear traction and when seeking a firmer rear mounting foundation for mid- to high-grip track setups.

This aluminum left rear bulk head suits racers who need a rigid rear mounting point on YZ-4S based chassis, and it integrates with the chassis' original layout without altering attachment locations.