FZ70S Disc Valve Replacement YSG1045 - YS Engine  [YSG1045]

FZ70S Intake disc valve overview

This YS Engine YSG1045 disc valve is a direct-fit replacement for the FZ70S family of two-stroke model engines. It functions as the intake timing and sealing element in disc-valve designs, restoring timing accuracy and sealing where the original disc is worn or damaged.

Fitting is a bench-level task: remove the engine's intake cover, withdraw the worn valve assembly, check mating faces for wear, and install the replacement making sure the disc is concentric with the crankcase port. Finish by verifying smooth disc rotation and correct clearance before reassembly and running.

On a tuned engine the disc valve controls intake timing and transient response; replacing a degraded disc can bring back consistent throttle feel and acceleration response. Inspect for nicks, warpage, and seal wear regularly as part of standard engine maintenance.