Athena S410485320002 High-Performance Crankshaft — 2002-2018 Yamaha YZ85 85cc

Athena — CNC Precision Engineering, Superior Steel Durability, and Factory-Spec Reliability

The crankshaft is the foundation of your engine's power, and for the high-revving Yamaha YZ85, only the highest manufacturing tolerances will do. The Athena S410485320002 Crankshaft is a premium replacement designed to restore and enhance the performance of your 85cc 2-stroke. Crafted using specialized high-grade steel and machined with state-of-the-art CNC technology, this crankshaft ensures perfect balance and structural integrity for competitive motocross use.

This unit features the standard 47.80 mm stroke, making it a drop-in replacement that maintains your engine’s original displacement and timing characteristics while offering the durability of modern materials. Whether you are performing a full bottom-end overhaul or replacing a failed OEM unit, Athena’s precision engineering minimizes vibration and maximizes energy transfer, giving your mini-racer the reliability needed to stay at the front of the pack.

• Manufactured from specialized high-tensile steel for maximum resistance to mechanical stress.
• CNC high-precision machining ensures exact tolerances and superior rotational balance.
• Standard 47.80 mm stroke length maintains factory-spec engine geometry.
• Designed specifically for the 2002-2018 Yamaha YZ85 85cc 2-stroke engine.
• Offers exceptional durability for high-RPM off-road and motocross riding styles.

Moto-House MX Pro Tip:

When replacing a crankshaft, the job isn't finished until you address the supporting components. We highly recommend installing new main bearings and high-quality crank seals along with this Athena unit to prevent air leaks and ensure a smooth spin. Before closing the cases, verify that the crank is centered and that there is no debris in the lubrication ports. A properly installed crankshaft is the difference between a podium finish and a "DNF."

Year	Make	Model Fitment
2002-2018	Yamaha	YZ85 / YZ85LW (Large Wheel)

FAQ Questions

Q) Does this crankshaft come pre-assembled with the connecting rod?
A) Yes, this is a complete, ready-to-install crankshaft assembly including the connecting rod and lower bearing.

Q) Is this a "Stroker" crank or standard size?
A) This is a standard stroke (47.80 mm) crankshaft, designed to meet the original factory specifications for the 2002-2018 YZ85.

Moto-House MX – Choice of Champions – is located in Clermont/Montverde, FL. We are the best motocross shop in Central Florida with lightning-fast shipping.