Sub Needle O-Ring for DZ170 CDI - YSE1275 by YS Engine  [YSE1275]

Sub-needle Seal for DZ170 CDI Engines

This YS Engine sub needle O-ring is supplied as a spare to restore sealing at the sub needle location on DZ170 CDI engines. It is intended as a direct replacement for the small O-ring used in the needle assembly to help retain consistent throttle and idle behaviour.

The listed compatibility refers specifically to the DZ170 CDI designation shown in the name. Do not presume fitment across other engine types without checking needle size and seat profile. This item is a single replacement part rather than a comprehensive service kit.

Fitting is suitable for hobbyist maintenance: remove the needle assembly, clean and inspect the seat and bore, fit the new O-ring, then reassemble and check the needle slides freely. Carry out stepwise carburettor adjustments and bench runs before full operation to confirm tuning results.

As a maintenance component, the O-ring helps keep the needle sealed for repeatable idle and mid-throttle settings; it will not change the main jetting or the fundamental needle calibration by itself.