{"product_id":"hot-rods-k021-main-crankshaft-bearing-and-seal-kit-yamaha-yz250f-moto-house-mx","title":"Hot Rods Main Crankshaft Bearing Kit K021 — Yamaha YZ250F \/ YZ250FX \/ WR250F \/ YZ450F 2001-2024","description":"\u003ch1\u003e\u003cstrong\u003eHot Rods Main Crankshaft Bearing Kit K021 — Yamaha YZ250F \/ YZ250FX \/ WR250F \/ YZ450F 2001-2024\u003c\/strong\u003e\u003c\/h1\u003e\n\n\u003ch2\u003eProduct Description\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eNote: As specified by the manufacturer for this particular model fitment configuration, this kit contains two precision main bearings only and does not include engine oil seals.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eAnchor your bottom end overhaul with the unmatched structural reliability of a Hot Rods Main Crankshaft Bearing Kit. When splitting your crankcases to replace a worn rod or drop in a fresh stroker assembly, cutting corners on the main bearings is never an option. This package stands as a \u003cstrong\u003eheavy-duty engine replacement solution\u003c\/strong\u003e, meticulously engineered to withstand the punishing lateral loads, high-RPM vibrations, and blistering thermal conditions common to high-performance Yamaha four-stroke dirt bikes.\u003c\/p\u003e\n\u003cp\u003eThis premium engine kit consists of two high-speed, precision-matched main crankshaft ball bearings built to strict factory tolerances. Designed to perfectly complement a new Hot Rods or OEM crankshaft assembly, these bearings minimize parasitic drag across the valvetrain, maintain absolute flywheel alignment, and ensure stable crank rotation. Whether you are attacking deep sandy tracks on a YZ250F or logging long technical trail hours on a WR, this kit delivers the structural integrity you need to ride with complete peace of mind.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eTop Features: Hot Rods Main Crankshaft Bearing Kit\u003c\/strong\u003e\u003cbr\u003e\no   Precision-matched pair of premium high-speed main crankshaft ball bearings.\u003cbr\u003e\no   Engineered to complement and complete a professional Hot Rods or factory OEM crankshaft installation.\u003cbr\u003e\no   Built to meet or exceed strict factory OEM dimensions for low-friction, high-RPM stability.\u003cbr\u003e\no   Crucial replacement component to eliminate crank vibration and prevent catastrophic case wear.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003ePlease review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eFitment List\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n    \u003cth\u003eYear Range\u003c\/th\u003e\n    \u003cth\u003eVehicle Brand\u003c\/th\u003e\n    \u003cth\u003eVehicle Model \u0026amp; Sub-Model\u003c\/th\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2001-2024\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eYZ250F\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2015-2024\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eYZ250FX\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2001-2024\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eWR250F\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2003-2015\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eYZ450F\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2008\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eWR250R\u003c\/td\u003e\n  \u003c\/tr\u003e\n  \u003ctr\u003e\n    \u003ctd\u003e2008\u003c\/td\u003e\n    \u003ctd\u003eYamaha\u003c\/td\u003e\n    \u003ctd\u003eWR250X\u003c\/td\u003e\n  \u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does this specific K021 kit include the outer crank oil seals?\u003c\/strong\u003e\u003cbr\u003e\nA: No. While some Hot Rods kits bundle seals, this particular application contains two precision main crankshaft ball bearings only. The crank oil seals must be sourced separately to complete your assembly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can I use these bearings with a stock factory Yamaha crankshaft assembly?\u003c\/strong\u003e\u003cbr\u003e\nA: Yes. These bearings are designed to factory OEM structural dimensions and fit perfectly with either stock Yamaha crankshafts or aftermarket Hot Rods assemblies.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What are the main signs that my crankshaft main bearings are wearing out?\u003c\/strong\u003e\u003cbr\u003e\nA: Excessive vibration vibrating through the footpegs or handlebars, a distinct rumbling or growling sound echoing from the bottom end, or noticeable up-and-down movement at the flywheel side when checking the ignition cavity.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eExpert Pro-Tip:\u003c\/strong\u003e Never attempt to force cold main bearings onto a cold crankshaft or into cold aluminum engine cases using a hammer—doing so will deform the bearing tracks and side-load the internal balls, ruining them before they ever run. Utilize thermal principles to your advantage: chill your crankshaft in a freezer overnight to shrink the metal journals slightly, and gently warm the engine case bearing bores to 250°F (120°C). The cold bearing will slip effortlessly into the warm engine case, and the cold crank will slide into place with minimal mechanical resistance.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eRecommended Pairings:\u003c\/strong\u003e\u003cbr\u003e\no    \u003ca href=\"https:\/\/motohousemx.com\/collections\/yamaha-yz250f-yz250fx-performance-parts-and-accessories\"\u003eYamaha YZ250F \/ YZ250FX Performance Parts \u0026amp; Upgrades\u003c\/a\u003e\u003cbr\u003e\no    \u003ca href=\"https:\/\/motohousemx.com\/collections\/yamaha-yz450f-performance-upgrades-engine-mods-and-accessories-moto-house-mx\"\u003eYamaha YZ450F Performance Parts\u003c\/a\u003e\u003cbr\u003e\no    \u003ca href=\"https:\/\/motohousemx.com\/collections\/mx-off-road-motorcycle-tools\"\u003ePremium Case Splitters \u0026amp; Bottom End Engine Tools\u003c\/a\u003e\u003c\/p\u003e\n\n\u003cp\u003eAt Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eMoto-House MX – Choice of Champions\u003c\/strong\u003e – Clermont \/ Montverde, FL. Central Florida's premier powersports source with lightning-fast worldwide shipping.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\/\",\n  \"@type\": \"Product\",\n  \"name\": \"Hot Rods Main Crankshaft Bearing Kit K021 — Yamaha YZ250F \/ YZ250FX \/ WR250F \/ YZ450F 2001-2024\",\n  \"image\": [],\n  \"description\": \"Premium Hot Rods main crankshaft ball bearing set engineered to fit a wide range of Yamaha four-stroke off-road models including YZ250F, YZ250FX, WR250F, and YZ450F.\",\n  \"sku\": \"K021\",\n  \"mpn\": \"K021\",\n  \"brand\": {\n    \"@type\": \"Brand\",\n    \"name\": \"Hot Rods\"\n  },\n  \"offers\": {\n    \"@type\": \"Offer\",\n    \"priceCurrency\": \"USD\",\n    \"itemCondition\": \"https:\/\/schema.org\/NewCondition\",\n    \"availability\": \"https:\/\/schema.org\/InStock\"\n  }\n}\n\u003c\/script\u003e","brand":"HOT RODS","offers":[{"title":"Default Title","offer_id":44174213447763,"sku":"K021","price":105.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1754\/5421\/files\/79317.png?v=1772933149","url":"https:\/\/motohousemx.com\/products\/hot-rods-k021-main-crankshaft-bearing-and-seal-kit-yamaha-yz250f-moto-house-mx","provider":"Moto-House MX","version":"1.0","type":"link"}