Yamaha YFM550 Grizzly Piston Kit - Wiseco - 10.25:1 CR, 92.00 mm Bore - `09-`13. This Wiseco piston kit is a direct-fit replacement for 2009–2013 YFM550 Grizzly models and is built for riders who want a durable, application-specific forged piston assembly.

Wiseco’s forged 4-stroke pistons are engineered for specific powersports engines and manufactured to tight tolerances. This kit is designed for a 92.00 mm bore and a 10.25:1 compression ratio, and it includes high-quality piston rings, wrist pin(s), and circlips for a complete install. The dedicated forging and machining process optimizes strength-to-weight and is carried out in Mentor, OH, USA. Ideal for engine rebuilds or performance-oriented rebuilds where factory-fit components and long-term service life are priorities.

Features

• Forged piston designed for Yamaha YFM550 Grizzly 2009–2013
• 92.00 mm bore, 10.25:1 compression ratio
• Includes piston rings, wrist pin(s), and circlips for a complete kit
• Machined to tight tolerances for consistent fitment
• Engineered, forged, and machined in the USA (Mentor, OH)

If you have questions about fitment, installation, or compatibility with modified engines, call us directly — we’re happy to help. We have two service locations where we offer installation and customization: Austin, Texas and the Los Angeles, California area. Call 512-982-9393 (TX) or 562-981-6800 (CA) to speak with a technician or to schedule service. If you're considering purchasing multiple items, contact us for shipping discounts. We install on premises at both locations.

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