Piston Pin Compatible With Various Motorcycle Atv Powersport Engines Wrist Pin Top End Rebuild Kit

Manufacturer Part Number:
04.1855.5

Pin Specifications:
• Outer Diameter: 18mm
• Length: 55.5mm
• Material: Case-hardened chrome steel

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
• Verify dimensions match your existing pin before installation
• Always replace circlips when removing pin

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

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