{"product_id":"piston-kit-yamaha-yfm-450-f-os-0-25-kodiak-grizzly-rhino","title":"Piston Kit OS 0.25 For Yamaha YFM 450F Kodiak Grizzly Rhino 2003 2014 OEM Replacement","description":"\u003cdiv\u003e\n\u003cp\u003eOS 0.25 oversize piston kit designed to rebuild the top end of 450cc four-stroke ATV engines. It restores compression and power across the mid-2000s to mid-2010s models, delivering reliable performance on trail chores and workdays. The.25 mm oversize compensates bore wear, helping to maintain a clean ring seal and smooth throttle response. Packaged as a complete top-end rebuild kit, it includes all necessary components for a straightforward installation.\u003c\/p\u003e\n\u003cp\u003eForged aluminum OS piston delivers proven strength and heat tolerance under harsh riding conditions, making this kit a dependable upgrade for a fleet or single rider alike. The kit includes the piston, rings, wrist pin, and circlips to provide a ready-to-install top-end package. Its broad compatibility across a 450cc-class ATV engine family means you can refresh multiple machines with one rebuild strategy, simplifying maintenance on a rural trail or farm fleet.\u003c\/p\u003e\n\u003ch3\u003eComprehensive Vehicle Fitment\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eManufacturer\u003c\/th\u003e\n\u003cth\u003eModels \/ Series\u003c\/th\u003e\n\u003cth\u003eYears \/ Details\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eYFM450 Kodiak\u003c\/td\u003e\n\u003ctd\u003e2003–2014\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eYFM450 Grizzly\u003c\/td\u003e\n\u003ctd\u003e2007–2014\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eYXR450 Rhino\u003c\/td\u003e\n\u003ctd\u003e2006–2010\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eYMF450 Wolverine\u003c\/td\u003e\n\u003ctd\u003e2006–2010\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003c\/h3\u003e\n\u003ch3\u003eProduct Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eAttribute\u003c\/th\u003e\n\u003cth\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOEM Reference Part Numbers\u003c\/td\u003e\n\u003ctd\u003eVaries by bore size and supplier; verify exact numbers on kit packaging or with your dealer.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003ePiston Kit (4-stroke)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eManufacturer\u003c\/td\u003e\n\u003ctd\u003eAftermarket Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eYFM450 Kodiak, Grizzly, Wolverine, Rhino top-end rebuilds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eForged aluminum alloy (commonly 2618)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePiston Size \/ Oversize\u003c\/td\u003e\n\u003ctd\u003eOS 0.25 (0.25 mm oversize)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInclusions\u003c\/td\u003e\n\u003ctd\u003e\n\u003cb\u003ePiston\u003c\/b\u003e, \u003cb\u003eRings\u003c\/b\u003e, \u003cb\u003eWrist Pin\u003c\/b\u003e, \u003cb\u003eCirclips\u003c\/b\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating \/ Finish\u003c\/td\u003e\n\u003ctd\u003eSkirt coating options (e.g., ArmorGlide in the aftermarket segment)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003c\/h3\u003e\n\u003ch3\u003eOEM \u0026amp; Aftermarket Cross-Reference Information\u003c\/h3\u003e\n\u003ctable style=\"width: 100%;\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth style=\"width: 21.6606%;\"\u003ePart Number\u003c\/th\u003e\n\u003cth style=\"width: 19.2174%;\"\u003eBrand \/ Type\u003c\/th\u003e\n\u003cth style=\"width: 58.5805%;\"\u003eCross-Reference Notes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 21.6606%;\"\u003eNA-40011-4\u003c\/td\u003e\n\u003ctd style=\"width: 19.2174%;\"\u003eNamura Piston Kit\u003c\/td\u003e\n\u003ctd style=\"width: 58.5805%;\"\u003eOversize +0.25 to +0.50 options exist; compatible with multiple 450cc Yamaha models; verify bore size on packaging.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 21.6606%;\"\u003e8904DA\u003c\/td\u003e\n\u003ctd style=\"width: 19.2174%;\"\u003eWossner Piston Kit\u003c\/td\u003e\n\u003ctd style=\"width: 58.5805%;\"\u003eYFM450 Kodiak\/Grizzly\/Wolverine\/Rhino applications; oversize options +0.50 and +1.00 available; includes rings, wrist pin, and circlips.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 21.6606%;\"\u003e4939M08450\u003c\/td\u003e\n\u003ctd style=\"width: 19.2174%;\"\u003eWiseco Piston Kit\u003c\/td\u003e\n\u003ctd style=\"width: 58.5805%;\"\u003e85.00 mm bore option (+0.50); includes piston, rings, wrist pin, and circlips; common cross-reference for 450cc Yamaha models.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 21.6606%;\"\u003eNA-40011-2\u003c\/td\u003e\n\u003ctd style=\"width: 19.2174%;\"\u003eNamura Piston Kit\u003c\/td\u003e\n\u003ctd style=\"width: 58.5805%;\"\u003eStandard to overweight fitment notes vary by model; consult catalog for exact match.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003c\/h3\u003e\n\u003ch3\u003eWhat’s Included\u003c\/h3\u003e\n\u003cp\u003eThis OS 0.25 piston kit ships with the essential components needed for a complete top-end rebuild.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cb\u003ePiston\u003c\/b\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cb\u003eRings\u003c\/b\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cb\u003eWrist Pin\u003c\/b\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cb\u003eCirclips\u003c\/b\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ci\u003eGaskets, seals, and timing components used in the full engine overhaul are not included; replace them as part of a complete top-end refresh.\u003c\/i\u003e\u003c\/p\u003e\n\u003ch3\u003eWhy Choose This Aftermarket Replacement?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eDirect-Fit Compatibility:\u003c\/b\u003e Precision oversize kit designed to restore OEM compression without modifying the cylinder or carriage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eOEM Cross-Reference:\u003c\/b\u003e Backed by multiple aftermarket brands that cover the same 450cc Yamaha platforms for flexible sourcing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eForged Aluminum Construction:\u003c\/b\u003e Strong, heat-tolerant 2618-grade aluminum forged piston for long life under harsh conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eComplete Top-End Rebuild Kit:\u003c\/b\u003e Includes piston, rings, wrist pin, and circlips for a turnkey installation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePremium Finishes \u0026amp; Coatings:\u003c\/b\u003e Skirt coatings and forged design help reduce scuffing and wear during break-in and everyday use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePerformance Restoration:\u003c\/b\u003e Restores original compression, power, and throttle response after bore wear.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation Notes:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eVerify bore size and confirm OS 0.25 suitability before ordering or installation.\u003c\/li\u003e\n\u003cli\u003eUse proper assembly lubrication on rings and wrist pin; avoid dry-fitting components.\u003c\/li\u003e\n\u003cli\u003eFollow the torque specifications from the service manual for wrist pins and any fasteners involved in the top-end assembly.\u003c\/li\u003e\n\u003cli\u003eInspect the cylinder bore for wear; if scoring or glazing is present, consider honing or re-boring per factory guidelines.\u003c\/li\u003e\n\u003cli\u003eReplace gaskets, seals, and the head gasket as part of a full top-end rebuild to ensure a reliable seal.\u003c\/li\u003e\n\u003cli\u003eRun a proper break-in procedure after installation to seat rings evenly and prevent scuffing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy Upgrade?\u003c\/h3\u003e\n\u003cp\u003eA worn piston and bore seal can rob compression, reduce power, and increase heat transfer as rings lose contact with the cylinder wall. Upgrading to this OS 0.25 piston kit restores compression, improves ring seal, and brings back the smooth power delivery you expect from a fresh top end, even after heavy trail or farm use. This rebuild restores reliability and helps prevent further engine scoring or heat-related wear by renewing the critical top-end components.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"ATV City","offers":[{"title":"Default Title","offer_id":57319258227062,"sku":"190.04392","price":89.33,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0971\/0302\/0406\/files\/image_2026-02-25_235500990.png?v=1774886126","url":"https:\/\/dgtagri.co.uk\/products\/piston-kit-yamaha-yfm-450-f-os-0-25-kodiak-grizzly-rhino","provider":"DGT Agri","version":"1.0","type":"link"}