{"product_id":"hz-gx390-gx340-fully-assembled-cylinder-head-kit-fits-honda-gx390-gx340-complete-gaskets-valves","title":"HZ GX390\/GX340 Fully Assembled Cylinder Head Kit — Fits Honda GX390 GX340, Complete Gaskets \u0026 Valves","description":"\u003cp\u003e\u003cstrong\u003eFully assembled replacement cylinder head kit for Honda GX340\/GX390 engines, ready to install with valves, gaskets, bolts and feeler gauges included.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis HZ GX390 cylinder head kit delivers a complete, drop-in head assembly compatible with Honda GX340 and GX390 engines and many common clones. It includes the cylinder head, valve cover, valves, valve springs, spark plug, insulation, full gasket sets, muffler gasket, all necessary bolts and nuts, and two feeler gauges for accurate valve clearance setup. The kit replaces Honda part numbers such as 12200-ZF6-406 and 12210-Z5T-416 and matches capacities from 337cc up to 459cc across OEM and clone applications.\u003c\/p\u003e\n\n\u003ch3\u003eWhat parts come in this fully assembled cylinder head kit?\u003c\/h3\u003e\n\u003cp\u003eThe HZ kit is intended to be a one-stop replacement for cylinder head rebuilds: you receive the head fully assembled so minimal prep is required before installation. All routine wear items that typically need replacing during a head service are included for convenience.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCylinder head and valve cover pre-assembled\u003c\/li\u003e\n  \u003cli\u003eIntake and exhaust valves, valve springs, rockers and pushrods\u003c\/li\u003e\n  \u003cli\u003eSpark plug, spark plug insulator and muffler studs\u003c\/li\u003e\n  \u003cli\u003eHead gasket, valve cover gasket, carburetor gasket set, muffler gasket\u003c\/li\u003e\n  \u003cli\u003eComplete set of bolts, nuts and washers\u003c\/li\u003e\n  \u003cli\u003eTwo feeler gauges for intake and exhaust clearance setting\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich engines and equipment will this head fit?\u003c\/h3\u003e\n\u003cp\u003eDesigned for Honda GX340 and GX390 engines, the HZ head also fits many aftermarket clone engines with similar bore\/stroke and mounting patterns. It is commonly used in pressure washers, water pumps, generators and compressors that use 11–16 horsepower small engines.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eHonda GX340, GX390 and GX390T\/GX340T variants\u003c\/li\u003e\n  \u003cli\u003eClone engines: 337cc, 338cc, 340cc, 389cc, 390cc, 420cc, 439cc, 458cc, 459cc\u003c\/li\u003e\n  \u003cli\u003eApplications: 4200–4400 psi pressure washers, water pumps, portable generators and air compressors\u003c\/li\u003e\n  \u003cli\u003eReplacement for Honda OEM numbers listed in product details\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does this assembled head save time and simplify installation?\u003c\/h3\u003e\n\u003cp\u003eReceiving the head pre-assembled means fewer individual parts to organize and less bench labor before engine reassembly. Factory-installed items like the spark plug and muffler studs reduce fitment steps; the included feeler gauges let you set valve lash precisely at install time.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePre-assembled valve train and fitted studs cut bench time\u003c\/li\u003e\n  \u003cli\u003eComplete gasket sets eliminate missing-seal delays\u003c\/li\u003e\n  \u003cli\u003eFeeler gauges ensure correct valve clearance on first run\u003c\/li\u003e\n  \u003cli\u003eAll mounting hardware provided to avoid extra trips for fasteners\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat should I check before buying to ensure fitment?\u003c\/h3\u003e\n\u003cp\u003eMeasure bolt-spacing, port orientation and overall head dimensions against your existing head to confirm compatibility. Cross-reference the OEM part numbers and engine displacement range in the listing with your engine model to avoid fitment issues.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompare mounting hole pattern and stud locations to your head\u003c\/li\u003e\n  \u003cli\u003eVerify engine model (GX340\/GX390) and displacement against listing\u003c\/li\u003e\n  \u003cli\u003eCheck compatibility with your equipment model (pump, generator, etc.)\u003c\/li\u003e\n  \u003cli\u003eConfirm required valve arrangement and spark plug position\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: This HZ assembled GX390 cylinder head kit is aimed at mechanics, fleet service technicians and DIY enthusiasts who need a complete, reliable replacement for worn or damaged GX340\/GX390 heads. It suits those repairing pressure washers, portable generators, water pumps and similar equipment who want a ready-to-install solution that includes gaskets, hardware and setup tools to minimize downtime.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does this HZ head fit Honda GX390 and GX340 engines?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. It’s designed for GX340\/GX390 and many clone engines with matching bolt patterns and displacements listed in the product details.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Are gaskets and bolts included?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. The kit includes head and valve cover gaskets, carburetor and muffler gaskets, plus all necessary bolts and nuts.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"HZ","offers":[{"title":"Default Title","offer_id":55171333128535,"sku":"B0BFXGX1H6","price":106.18,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/hz-gx390-head-front-assembly.jpg?v=1790442972","url":"https:\/\/britishgarage.co.uk\/products\/hz-gx390-gx340-fully-assembled-cylinder-head-kit-fits-honda-gx390-gx340-complete-gaskets-valves","provider":"British Garage","version":"1.0","type":"link"}