{"product_id":"harley-davidson-x440t-head-cover-gasket-hdh12391acj000s","title":"Harley-Davidson X440T Head Cover Gasket HDH12391ACJ000S | Genuine Rocker Cover Gasket","description":"\u003ch2\u003eHarley-Davidson X440T Head Cover Gasket – HDH12391ACJ000S\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eReplace a leaking, hardened, flattened or damaged cylinder-head \/ rocker-cover gasket with the correct genuine Harley-Davidson X440T gasket.\u003c\/strong\u003e Part number \u003cstrong\u003eHDH12391ACJ000S\u003c\/strong\u003e is identified in the supplied X440T parts list as \u003cstrong\u003eGASKET HEAD COVER\u003c\/strong\u003e. In buyer language, this is commonly searched as a \u003cstrong\u003ehead cover gasket\u003c\/strong\u003e, \u003cstrong\u003erocker cover gasket\u003c\/strong\u003e, \u003cstrong\u003evalve cover gasket\u003c\/strong\u003e, or \u003cstrong\u003etappet cover gasket\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eThis listing is built around both the official catalogue wording and the terms owners, mechanics and workshops actually use when searching online: \u003cstrong\u003eHarley X440T head cover gasket\u003c\/strong\u003e, \u003cstrong\u003eX440T rocker cover gasket\u003c\/strong\u003e, \u003cstrong\u003eX440T valve cover gasket\u003c\/strong\u003e, \u003cstrong\u003eHarley X440T engine top cover gasket\u003c\/strong\u003e, and the exact OEM reference \u003cstrong\u003eHDH12391ACJ000S\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eThe head-cover gasket seals the joint between the engine's cylinder head and the removable top cover. Its job is to help keep engine oil contained inside the valve \/ rocker area while preventing oil seepage around the cover joint. A worn or damaged gasket can lead to visible oil sweating or leakage around the top of the engine.\u003c\/p\u003e\n\u003ch3\u003eProduct Identity\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Harley-Davidson\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e HDH12391ACJ000S\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOfficial Catalogue Description:\u003c\/strong\u003e GASKET HEAD COVER\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCommon Search Names:\u003c\/strong\u003e Head Cover Gasket \/ Rocker Cover Gasket \/ Valve Cover Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication Area:\u003c\/strong\u003e Cylinder-head top cover \/ valve-train cover sealing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 piece\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eConfirmed Compatibility\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eHarley-Davidson X440T – January 2026 \/ R4AA\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFitment note:\u003c\/strong\u003e the supplied X440T catalogue confirms this SKU for the January 2026 X440T application. Do not assume compatibility with another X440 generation only because the gasket looks similar; use the exact part number whenever possible.\u003c\/p\u003e\n\u003ch3\u003eWhat This Gasket Does\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSeals the joint between the head cover and cylinder head\u003c\/li\u003e\n\u003cli\u003eHelps prevent engine-oil seepage from the valve \/ rocker area\u003c\/li\u003e\n\u003cli\u003eMaintains the intended sealed top-end environment\u003c\/li\u003e\n\u003cli\u003eProvides the correct shape and sealing profile for the specified application\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhen Should It Be Replaced?\u003c\/h3\u003e\n\u003cp\u003eReplacement is commonly considered when:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eOil is visible around the head-cover joint\u003c\/li\u003e\n\u003cli\u003eThe gasket has hardened, flattened, cracked or torn\u003c\/li\u003e\n\u003cli\u003eThe head cover has been removed for inspection or top-end service and the old gasket is no longer serviceable\u003c\/li\u003e\n\u003cli\u003eThere is oil staining or seepage from the upper engine area\u003c\/li\u003e\n\u003cli\u003eA previous repair used sealant or an incorrect gasket and the joint is leaking\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eImportant – Gasket Only\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHDH12391ACJ000S is the head-cover gasket only.\u003c\/strong\u003e It is not the complete cylinder-head cover and it is not a full engine gasket kit.\u003c\/p\u003e\n\u003cp\u003eDo not confuse this part with:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eBreather plate gasket\u003c\/li\u003e\n\u003cli\u003eBreather plate\u003c\/li\u003e\n\u003cli\u003eCylinder-head gasket\u003c\/li\u003e\n\u003cli\u003eComplete engine gasket kit\u003c\/li\u003e\n\u003cli\u003eHead-cover bolts or washers\u003c\/li\u003e\n\u003cli\u003eOil seals or O-rings used elsewhere in the engine\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy Exact Part-Number Matching Matters\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eEngine gaskets can look very similar but differ in profile and sealing points\u003c\/li\u003e\n\u003cli\u003eAn incorrect gasket can cause oil leakage or poor cover seating\u003c\/li\u003e\n\u003cli\u003eExact SKU matching reduces wrong-part returns\u003c\/li\u003e\n\u003cli\u003eCorrect genuine fitment avoids trimming or modifying a universal gasket\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhat’s in the Box\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 x Genuine Harley-Davidson X440T Head Cover Gasket\u003c\/li\u003e\n\u003cli\u003ePart number: \u003cstrong\u003eHDH12391ACJ000S\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eClean the mating surfaces before installation\u003c\/li\u003e\n\u003cli\u003eDo not damage or pinch the new gasket while positioning the cover\u003c\/li\u003e\n\u003cli\u003eInspect the head cover and mating surface for distortion or old gasket residue\u003c\/li\u003e\n\u003cli\u003eTighten cover fasteners evenly and to the correct workshop specification\u003c\/li\u003e\n\u003cli\u003eAvoid excessive sealant unless the service procedure specifically requires it\u003c\/li\u003e\n\u003cli\u003eAfter installation, inspect for oil seepage once the engine has been run\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eReturn Prevention Note\u003c\/h3\u003e\n\u003cp\u003ePlease match \u003cstrong\u003eHDH12391ACJ000S\u003c\/strong\u003e and confirm you require the \u003cstrong\u003eGASKET HEAD COVER\u003c\/strong\u003e. If you need the head gasket, breather gasket, complete cover or another engine seal, those are separate parts.\u003c\/p\u003e\n\u003ch3\u003eFAQs\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e1. What is HDH12391ACJ000S?\u003c\/strong\u003e\u003cbr\u003eIt is the genuine \u003cstrong\u003ehead cover gasket\u003c\/strong\u003e listed for the Harley-Davidson X440T.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Is this also called a rocker cover gasket?\u003c\/strong\u003e\u003cbr\u003eYes. Buyers and mechanics may refer to this type of part as a \u003cstrong\u003erocker cover gasket\u003c\/strong\u003e or \u003cstrong\u003evalve cover gasket\u003c\/strong\u003e, while the catalogue description is \u003cstrong\u003eGASKET HEAD COVER\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Which motorcycle is confirmed?\u003c\/strong\u003e\u003cbr\u003eThe supplied parts list confirms \u003cstrong\u003eHarley-Davidson X440T – January 2026 \/ R4AA\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e4. Is this the cylinder-head gasket?\u003c\/strong\u003e\u003cbr\u003eNo. The cylinder-head gasket seals a different joint in the engine. This part seals the removable head \/ rocker cover.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e5. Can this help fix oil seepage from the top of the engine?\u003c\/strong\u003e\u003cbr\u003eIf the seepage is coming from the head-cover joint and the existing gasket is worn or damaged, replacing the correct gasket is part of the repair. The mating surfaces and cover condition should also be inspected.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e6. Should the gasket be reused after removing the head cover?\u003c\/strong\u003e\u003cbr\u003eIf the old gasket is hardened, damaged, compressed, torn or no longer sealing correctly, replacement is the safer choice.\u003c\/p\u003e\n\u003cp\u003eHarley X440T head cover gasket, X440T rocker cover gasket, X440T valve cover gasket, Harley X440T tappet cover gasket, X440T engine top cover gasket, GASKET HEAD COVER, HDH12391ACJ000S.\u003c\/p\u003e","brand":"Harley-Davidson","offers":[{"title":"Default Title","offer_id":52186266468647,"sku":"HDH12391ACJ000S","price":70.0,"currency_code":"INR","in_stock":true}],"url":"https:\/\/underthehood.co.in\/products\/harley-davidson-x440t-head-cover-gasket-hdh12391acj000s","provider":"UNDER THE HOOD","version":"1.0","type":"link"}