YS Engine YSS7121 Throttle Barrel 61ST-H Spare Part  [YSS7121]

Throttle barrel — carburettor spare

The YS Engine YSS7121 throttle barrel is an RC-scale replacement component designed for fitment within YS Engine carburetor assemblies. It replaces the barrel that forms the throttle slide bore and interfaces with the throttle plate; the description is presented as neutral technical information for hobby workshops.

Made in an aluminium-style construction to help retain bore geometry and encourage smooth throttle action, the barrel should be installed after inspecting the throttle slide and linkages for wear. Remove the carburettor from the model, fit the new barrel to the carburettor body, and ensure the throttle moves freely through its complete range before refitting to the engine. Confirm the YSS7121 part code against your carburettor casting prior to ordering.

During tuning and maintenance this spare aids consistent throttle response and steady idle by preserving bore shape and reducing irregular airflow at partial throttle positions. Keep one as a workshop spare for restoring reliable throttle actuation on glow-engine RC models.