YS Engine 91SR Throttle Barrel YSS9121 Slide Replacement  [YSS9121]

91SR throttle barrel technical summary

This YS Engine YSS9121 throttle barrel is an aftermarket replacement tailored for 91SR engines and functions as the carburetor's throttle slide. It directly affects airflow metering and the engine's throttle feel under all operating conditions.

Intended compatibility is restricted to the 91SR family. Confirm the slide dimensions and linkage arrangement on your carburetor before fitting to ensure proper travel and clearance.

Fitting tips: remove the carburetor from the model for a clean workspace, inspect mating surfaces, and transfer the slide while keeping its orientation intact. After reassembly, check for smooth, full-range linkage motion and make any small adjustments to idle or linkage geometry to restore expected behavior.

Role in tuning: a correctly fitting throttle barrel helps stabilise idle and improves transient response; replacing degraded slides simplifies achieving consistent carburetor settings. Regular light cleaning and inspection will prolong consistent operation.