Piston Pin Compatible With 2001-2015 Gas Gas Ec-F 250 Yamaha Wr-F 250 Yz-F 250 16Mm Wrist Pin

Manufacturer Part Number:
04.1644.4

Cross-Reference OEM Part Numbers:
Yamaha: 5NL-11633-00-00

Pin Specifications:
• Outer Diameter: 16mm
• Material: Case-hardened chrome steel
• Surface Finish: Mirror-polished for minimal friction

Engine Specifications:
• 249cc DOHC 4-Valve 4-Stroke Single Cylinder — Liquid Cooled
• Bore × Stroke: 77mm × 53.6mm
• Compression Ratio: 12.4:1 (YZ-F), 11.8:1 (WR-F)

Notes:
• Piston pin (wrist pin) connects piston to connecting rod small end
• Replace during top-end rebuild or when pin shows wear, scoring, or discoloration
• Gas Gas EC-F 250 uses a Yamaha-sourced 4-stroke engine — same piston pin as YZ-F/WR-F
• Always replace piston pin circlips when removing pin — never reuse old circlips

Function:
The piston pin (also called a wrist pin or gudgeon pin) is the hardened steel shaft that connects the piston to the connecting rod small end. It transfers combustion force from the piston to the connecting rod while allowing the rod to pivot as the crankshaft rotates. A worn, scored, or loose piston pin causes knocking noise, accelerated bore wear, and potential catastrophic engine failure.

When to Replace:
• During any top-end rebuild (piston, rings, cylinder re-bore/re-plate)
• When pin shows visible wear, scoring, discoloration, or blue heat marks
• When pin has measurable play in the connecting rod small end bearing
• Recommended every 2nd piston replacement even if pin appears serviceable

Installation Notes:
• Always replace piston pin circlips — never reuse old circlips
• Apply assembly oil or two-stroke premix to pin before installation
• Ensure circlips are fully seated in their grooves — improper seating causes engine damage
• Verify connecting rod small end bearing condition before reassembly

PRODUCT NOTICE:
As a parts distributor we mostly sell aftermarket parts (any OEM parts would be noted as such). Aftermarket parts are not sourced from the original vehicle or equipment manufacturer, but are designed to function the same as - if not better than - the original. All parts sold are new.

WARNING - This product may expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov