2V91W-F/K Piston

CFMoto 2V91W-F/K Piston

Part Numbers: 0JWV-040001-3001-Q0-00001 / 0JWV-040001-3001-Q0-00002

🔧 Engine Piston · For 800/850cc Models · OEM Spec

This is a genuine CFMoto Piston, part numbers 0JWV-040001-3001-Q0-00001 and 0JWV-040001-3001-Q0-00002. These pistons are designed for CFMoto ATV and UTV models equipped with 2V91W-F or 2V91W-K engines, with displacements covering 800cc and 850cc. The piston is the heart of the engine, enduring high-temperature, high-pressure combustion forces and transferring power through the connecting rod to the crankshaft. These OEM pistons are made from high-strength aluminum alloy (forged/cast) and precision-machined. Paired with original piston rings, they ensure combustion chamber sealing, oil control, and heat dissipation. The two part numbers likely represent different size grades (such as standard size or oversize for rebuilds). Choose according to the actual wear condition of your engine.

These Pistons (0JWV-040001-3001-Q0-00001/00002) fit the following CFMoto models:

• OEM Design: Piston crown shape, compression height, and pin bore location strictly follow original engine design, ensuring correct compression ratio and valve timing.
• High-Quality Material: Made from eutectic Al-Si alloy or higher-performance materials, offering excellent high-temperature strength, wear resistance, and thermal conductivity.
• Precision Machining: Skirt features a special elliptical shape and surface coating to reduce friction and improve scuff resistance.
• Complete Kit: Includes piston rings with optimized material and tension for effective oil control and sealing.
• Multiple Sizes: Available in standard and oversize versions to meet rebuild requirements for engines with varying wear levels.

🛑 Effects of Piston Wear & When to Replace

As engine mileage increases, wear in the ring grooves can cause increased blow-by and oil consumption; skirt wear may lead to piston slap (knocking noise). When symptoms like hard starting, power loss, excessive oil consumption, or blue smoke appear, the engine typically needs to be disassembled to measure cylinder bore and piston-to-cylinder clearance. Replacing with an OEM piston assembly is the fundamental way to restore engine performance. Using non-OEM or incorrectly sized pistons can result in seizure, scoring, or complete engine failure.

⚠️ Critical Installation Note: Piston installation requires specialized tools and expertise. Piston-to-cylinder clearance, ring end gap, and side clearance MUST be measured according to the service manual. Ensure circlips are fully seated in their grooves. Ring gaps should be staggered at the specified angle. We strongly recommend installation by a professional technician experienced in engine overhaul.