JE Pistons 260955 FSR Pro Series Forged Piston Kit - 97.00mm 12.5 1

The JE Pistons 260955 FSR Pro Series Piston Kit delivers race-proven forged performance in a precision-engineered single-cylinder kit. Forged from 2618 aluminum alloy, this piston offers the high tensile strength required for demanding, high-performance powersports applications. Engineered, forged, and machined entirely in the USA, every JE piston is purpose-built for its specific engine to strike the ideal balance of durability and peak output.

The FSR (Forged Side Relief) Pro Series design reduces skirt width to minimize friction and parasitic power loss, while also trimming overall piston weight. With a 97.00mm bore diameter, flat-top piston head, and a 12.5:1 compression ratio, this kit is tailored for riders demanding maximum performance from a 450cc single-cylinder engine.

Key Features:

• 2618 forged aluminum construction — high tensile strength for high-load performance use
• Proprietary FSR (Forged Side Relief) forging — reduces skirt friction and saves weight
• Flat-top piston head with smooth radius dome and dish designs
• Radiused valve reliefs for optimized flow clearance
• Precision CNC-machined ring grooves for consistent ring seal
• Machined oil drain-back holes engineered for controlled oil management
• Factory-honed pin bore with included wrist pin (19mm / 0.748 in. diameter) and locks
• 97.00mm (3.819 in.) bore diameter — standard bore
• 12.5:1 compression ratio
• Compatible with 4-valve 450cc cylinder head configuration
• Piston average weight: 262 grams
• Pin wall thickness: 0.160 in.
• Top compression ring thickness: 0.0285 in. | Oil ring thickness: 0.0795 in.
• Ringset sold separately (OEM ring compatible) | Wrist pin and locks included
• Designed and manufactured in the USA

The JE Pistons FSR Pro Series represents a dedicated forging program built specifically for high-revving, race-focused applications. Whether for closed-course competition or serious trail use, this kit provides the reliability and power-density serious riders demand.