{"product_id":"wossner-8321d100-piston-kit-2022-2026-yamaha-yz125-yz125x-1-00mm-oversize","title":"Wossner 8321D100 Piston Kit - 2022-2026 Yamaha YZ125 YZ125X +1.00mm Oversize","description":"\u003ch3\u003eWossner 8321D100 Standard Series Forged 2-Stroke Piston Kit - +1.00mm Oversize\u003c\/h3\u003e\n\n\u003cp\u003eSave your cylinder or gain a performance edge with the Wossner 8321D100 Piston Kit. Specifically engineered for the latest generation 2022-2026 Yamaha YZ125 and YZ125X models, this +1.00mm oversize forged kit is the professional choice for cylinders that have been bored or replated to 55.00mm. At Moto-House MX, we know that when a cylinder sustains damage or requires a significant refresh, Wossner’s aerospace-grade forged components provide the precision and reliability needed to get your machine back on the podium.\u003c\/p\u003e\n\n\u003cp\u003eForged from aerospace-grade aluminum alloy, the 8321D100 features a performance-driven single-ring design to minimize friction and maximize RPM potential. Despite the larger diameter, Wossner utilizes optimized machining to keep the piston lightweight, ensuring your YZ retains its signature snappy throttle response. The permanent skirt coating reduces internal drag and piston rock, which is especially critical in oversize applications for maintaining a quiet engine and smooth break-in. This 54.95mm piston is precision-matched for 55.00mm bores, offering a durable solution for high-performance engine builds.\u003c\/p\u003e\n\n\u003ch3\u003eTop Features: Wossner 8321D100 Piston Kit\u003c\/h3\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cb\u003e+1.00mm Oversize (54.95mm):\u003c\/b\u003e Designed specifically for 55.00mm bores, perfect for repairing damaged cylinders or custom engine builds.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eSingle Ring Design:\u003c\/b\u003e Reduces internal friction and drag, allowing for the rapid revving and peak power that 125cc racers demand.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eAerospace-Grade Forging:\u003c\/b\u003e Significantly stronger than stock cast pistons, providing superior fatigue resistance for high-RPM racing.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eLow-Friction Skirt Coating:\u003c\/b\u003e Permanent molybdenum disulphide coating protects the cylinder wall and ensures consistent performance under high heat.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eOptimized Strength-to-Weight:\u003c\/b\u003e Machined to remove unnecessary weight while reinforcing the crown and skirt for long-lasting durability.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eComplete Assembly:\u003c\/b\u003e Kit includes the forged piston, high-performance ring, wrist pin, and circlips.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cb\u003eExpert Pro-Tip:\u003c\/b\u003e Moving to a +1.00mm oversize requires the cylinder to be professionally bored and replated to a 55.00mm finished size. This is an excellent way to save an expensive YZ125 cylinder that has deep scoring. When installing the 8321D100, always verify your ring end gap and ensure your power valve is clear of the larger piston diameter. Pairing this build with a fresh top-end gasket kit and premium 2-stroke premix oil will keep your Yamaha screaming at the front of the pack.\u003c\/p\u003e\n\n\u003ch3\u003eFitment List\u003c\/h3\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" style=\"width: 100%; border-collapse: collapse;\"\u003e\n    \u003cthead\u003e\n        \u003ctr\u003e\n            \u003cth\u003eYear Range\u003c\/th\u003e\n            \u003cth\u003eVehicle Brand\u003c\/th\u003e\n            \u003cth\u003eVehicle Model\u003c\/th\u003e\n        \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e2022-2026\u003c\/td\u003e\n            \u003ctd\u003eYamaha\u003c\/td\u003e\n            \u003ctd\u003eYZ125 (Standard, Monster Energy, 50th\/70th Anniversary)\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e2023-2026\u003c\/td\u003e\n            \u003ctd\u003eYamaha\u003c\/td\u003e\n            \u003ctd\u003eYZ125X (Cross Country)\u003c\/td\u003e\n        \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cb\u003eQ: Is this a drop-in replacement for a stock cylinder?\u003c\/b\u003e\u003cbr\u003e\nA: No, this is a +1.00mm oversize piston. Your cylinder must be bored and replated to 55.00mm to accommodate this piston kit.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003eQ: Why choose an oversize Wossner piston?\u003c\/b\u003e\u003cbr\u003e\nA: It allows you to refurbish a damaged cylinder rather than buying a new one. Wossner’s forged construction ensures that even at a larger size, the piston can handle the intense stresses of a 125cc race engine.\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003eQ: Does this kit include the gasket set?\u003c\/b\u003e\u003cbr\u003e\nA: No, the kit includes the forged piston, ring, wrist pin, and clips. A complete top-end gasket set is sold separately and is required for a professional rebuild.\u003c\/p\u003e\n\n\u003ch3\u003eRecommended Pairings\u003c\/h3\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cb\u003eComplete Top End Gasket Set:\u003c\/b\u003e Ensure a professional, leak-free seal for your engine refresh.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cb\u003eYamalube 2-R Premix Oil:\u003c\/b\u003e The gold standard for keeping high-performance Yamaha 2-strokes running clean and protected.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eRestore your machine’s power and precision today. Buy now at Moto-House MX!\u003c\/p\u003e\n\n\u003cp\u003e\u003cb\u003eMoto-House MX – Choice of Champions\u003c\/b\u003e – is located in Clermont\/Montverde, FL. The Best Motocross\/UTV \u0026amp; ATV Shop in Central Florida. Stop by our local store in Montverde, FL or enjoy lightning-fast shipping across the USA.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\/\",\n  \"@type\": \"Product\",\n  \"name\": \"Wossner 8321D100 Piston Kit\",\n  \"image\": [],\n  \"description\": \"Premium Wossner 8321D100 Forged 2-Stroke Single Ring Piston Kit for 2022-2026 Yamaha YZ125 and YZ125X. +1.00mm Oversize (54.95mm) for 55.00mm bore.\",\n  \"sku\": \"8321D100\",\n  \"brand\": {\n    \"@type\": \"Brand\",\n    \"name\": \"Wossner\"\n  },\n  \"offers\": {\n    \"@type\": \"Offer\",\n    \"url\": \"https:\/\/motohousemx.com\/products\/wossner-8321d100-piston-kit\",\n    \"priceCurrency\": \"USD\",\n    \"availability\": \"https:\/\/schema.org\/InStock\"\n  }\n}\n\u003c\/script\u003e","brand":"WOSSNER","offers":[{"title":"Default Title","offer_id":44495999369299,"sku":"8321D100","price":132.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1754\/5421\/files\/2756509.png?v=1776229994","url":"https:\/\/motohousemx.com\/products\/wossner-8321d100-piston-kit-2022-2026-yamaha-yz125-yz125x-1-00mm-oversize","provider":"Moto-House MX","version":"1.0","type":"link"}