Hitachi Mouth Washer - 323-729

Hitachi part 323-729 (323729) — Mouth Washer. This is the original Hitachi metal ring that sits at the front of the cylinder assembly on select Hitachi/Hikoki rotary hammers; it replaces the worn mouth washer that locates the shank sleeve and helps seal the front of the hammer assembly.

Fits example models: H65SB2 and H65SD2.

Details: single-piece stamped metal washer (sold individually) that installs immediately ahead of the shank sleeve (part number 323-730) and O‑ring in the front cylinder area — a simple, direct replacement to restore correct fit and front-end sealing. Condition is listed as original Hitachi.

Quick to fit: remove the front cover/cylinder parts, swap the old mouth washer for this original Hitachi 323-729 and reassemble — restores correct positioning of the shank sleeve and front sealing surfaces so the tool runs as intended.