Wiseco PK1382 4-Stroke Forged Piston Kit 77.00mm Bore 13.5:1 CR +.75 Overbore

The Wiseco PK1382 is a 4-Stroke Forged Series Piston Kit featuring a 77.00 mm bore and 13.5:1 compression ratio, representing a +.75mm overbore (bore code 4858M). Designed for high-performance dirt bike applications, this kit delivers the precision, strength, and durability that serious motorsport riders demand.

Kit Includes:

• Forged aluminum piston
• Piston rings
• Wrist pin
• Wrist pin circlips
• Top-end gasket kit

Key Features:

• USA-forged construction — All Wiseco pistons are forged in-house using proprietary tooling, ensuring tight quality control from raw material to finished part
• High-silicon, low-expansion aluminum alloy — Provides superior strength, reduced weight, improved heat transfer, and extended service life compared to cast pistons
• ArmorGlide skirt coating — A high-tech friction-reducing coating that allows tighter bore fitment, minimizes piston rock, and improves wear resistance
• CNC diamond-turned machining — High-speed CNC Diamond Turning Centers hold exact tolerances with no size variation between parts
• Closer wrist pin boss spacing — Eliminates wrist pin flex for more precise, reliable power transfer
• Waffle-design forged dome — Reinforced dome geometry improves heat transfer and adds structural strength under high-compression conditions
• Optimized strength-to-weight ratio — Each forging is engineered to maximize performance without adding unnecessary mass

Unlike cast pistons, Wiseco forgings feature a condensed, aligned grain structure that delivers higher mechanical properties and superior resistance to impact and fatigue. The result is a piston that holds up under the extreme heat and stress of high-performance 4-stroke engines. Wiseco's in-house dyno testing program validates every design, ensuring real-world performance gains in horsepower, torque, and reliability.