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

Sub needle O-ring for DZ170 CDI

This YS Engine sub needle O-ring is an RC-scale spare intended to restore the sealing function around the sub needle area of DZ170 CDI engines. It serves as a simple replacement item for the needle assembly where an O-ring seal is required, helping maintain predictable needle response during throttle and idle adjustments.

Compatibility is limited to the DZ170 CDI designation listed in the product name. Do not assume fitment with other engine families without verification of needle dimensions and seat geometry. This part is sold as a small replacement component, not a service kit.

Installation is straightforward for hobby-level maintenance: remove the needle assembly, inspect the needle seat and bore for wear or debris, replace the O-ring, then reassemble and check needle movement. After installation, perform incremental carburettor adjustments and bench checks before full-run testing to confirm tuning behavior.

For tuning, treat the O-ring as a maintenance item that preserves needle seal integrity; it supports consistent idle and mid-throttle adjustments but does not alter jetting or main-needle characteristics on its own.