ProX Piston Kit (96.95mm / Size A / 12.8:1) 01.2448.A - 2018-2019 Yamaha YZ450F - 2018-2020 WR450F / YZ450FX

Product Description

The ProX 01.2448.A Piston Kit is engineered as a precision top-end solution for Yamaha 450cc four-stroke platforms requiring a Standard Size A bore profile. Manufactured from dedicated aluminum alloy, this 96.95mm piston assembly matches factory tolerances for running inside a standard 97.00mm cylinder sleeve or plated bore. Designed to maintain the factory 12.8:1 compression ratio, this assembly provides immediate combustion seal and mechanical stability across high-RPM motocross and off-road operating conditions.

Each piston is machined using CNC equipment to ensure uniform skirt geometry, proper ring land dimensions, and accurate pin bore alignment. The included piston rings are produced in original equipment facilities to strict material specifications, guaranteeing optimal cylinder wall seating and heat transfer. The complete kit includes the piston, ring pack, wrist pin, circlips, and an instruction sheet to service your four-stroke motor during routine top-end maintenance or complete teardowns.

Top Features: ProX Piston Kit

• Manufactured from aluminum alloy and machined on CNC equipment for tight dimensional accuracy.
• Standard Size A 96.95mm piston engineered for standard 97.00mm bore cylinder applications.
• Maintains the stock 12.8:1 compression ratio across 450cc Yamaha four-stroke engines.
• Includes dedicated piston rings manufactured in OEM facilities to factory specifications.
• Supplied as a complete top-end package with piston, ring set, wrist pin, circlips, and instruction sheet.

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: What cylinder bore size does this Size A piston require?
A: This 96.95mm Size A piston is designed for a standard 97.00mm cylinder bore, providing the specified running clearance for standard cylinder diameters.

Q: What components are supplied in the ProX kit?
A: The kit comes complete with the aluminum alloy piston, piston ring set, wrist pin, a pair of circlips, and an instruction sheet.

Q: Does this piston change the factory compression ratio on my Yamaha 450?
A: No, this assembly maintains the factory-specified 12.8:1 compression ratio.

Expert Pro-Tip: Before installing any four-stroke piston into a plated cylinder, always check your ring end gap by squaring each ring in the cylinder bore about an inch down using the piston crown. Use a feeler gauge to verify gap clearance according to the included ProX instruction sheet. When seating the wrist pin circlips, ensure the open gap points downward toward the 6 o'clock position (or upward at 12 o'clock), never inline with the pin thrust motion, and double-check that the clip is fully seated inside its groove before cylinder installation.

Recommended Pairings:

• Yamaha YZ450F Performance Parts & Upgrades
• Yamaha 4-Stroke Performance Parts
• Motorcycle Tools Performance Parts & Upgrades

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