{"product_id":"piston-ring-kit-honda-trx-400-os-0-25-1995-2003","title":"Piston Ring Kit 0.25 Oversize For Honda TRX 400 Foreman 1995 2003 TRX400FW Replacement Engine Sealing","description":"\u003cdiv\u003e\n\u003cp\u003eRestore peak compression and reliable sealing in Honda TRX400FW Foreman 4x4 engines built between 1995 and 2003 with a piston ring kit sized for a 0.25 oversize bore. Replacing worn piston rings that have lost tension eliminates blow-by and oil leakage, helping recover factory-like power, throttle response, and smooth operation. Designed to meet OEM specifications while delivering the durability and value of an aftermarket solution, this kit is a practical upgrade for trail rides, farm duty, and weekend work alike. The 0.25 oversize rings bring bore seating back to proper specification, restoring accurate clearance and sealing under rugged conditions.\u003c\/p\u003e\n\u003cp\u003eThese rings address common wear-and-tear problems that plague mid-life TRX Foreman engines—ring tension loss, glazing, and imperfect sealing that lead to compression drop and higher oil consumption. An aftermarket replacement that uses robust materials and precise tolerances helps you regain reliable performance for demanding off-road tasks and daily farm use, with a cost-effective rebuild path that minimizes downtime.\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\u003eHonda\u003c\/td\u003e\n\u003ctd\u003eTRX400FW Foreman 4x4\u003c\/td\u003e\n\u003ctd\u003e1995-2003\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHonda\u003c\/td\u003e\n\u003ctd\u003eTRX Foreman 400 Series (4x4)\u003c\/td\u003e\n\u003ctd\u003eMid-1990s to early-2000s variants\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHonda\u003c\/td\u003e\n\u003ctd\u003eTRX400F \/ TRX Foreman 400 (4x4)\u003c\/td\u003e\n\u003ctd\u003e1995-2003\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHonda\u003c\/td\u003e\n\u003ctd\u003eTRX Foreman 400 Engines\u003c\/td\u003e\n\u003ctd\u003e1995-2003\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eFitment notes pulled from commonly referenced listings for the TRX400FW Foreman 4x4 platform from 1995 through 2003. These sources corroborate the era and single-cylinder nature of the engine family these rings are designed for.\u003c\/p\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\u003e13021-HM7-003; 13021-HM7-004\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003ePiston Ring Kit (0.25 Oversize)\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\u003eHonda TRX400FW Foreman 4x4 (1995-2003)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOversize\u003c\/td\u003e\n\u003ctd\u003e0.25 mm over standard bore\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRing Configuration\u003c\/td\u003e\n\u003ctd\u003e2 x Compression Rings + 1 x Oil Ring per cylinder\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eHigh-grade steel alloy with chrome-plated compression rings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBore Size (standard)\u003c\/td\u003e\n\u003ctd\u003e86.00 mm (bore standard for TRX400FW); oversize yields ~86.25 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCylinder Count\u003c\/td\u003e\n\u003ctd\u003e1-cylinder engine\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eNotes: The standard bore for these TRX400 engines is 86.00 mm; selecting a 0.25 oversize kit targets an approximate bore of 86.25 mm to restore proper clearance and seating. OEM references and cross-reference notes are provided in the cross-reference table below.\u003c\/p\u003e\n\u003ch3\u003eOEM \u0026amp; Aftermarket Cross-Reference Information\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003ePart Number\u003c\/th\u003e\n\u003cth\u003eBrand \/ Type\u003c\/th\u003e\n\u003cth\u003eCross-Reference Notes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e13021-HM7-003\u003c\/td\u003e\n\u003ctd\u003eRIKEN\u003c\/td\u003e\n\u003ctd\u003e0.25 oversize piston ring set; OEM-equivalent in aftermarket form\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e13021-HM7-004\u003c\/td\u003e\n\u003ctd\u003eTEIKOKU\u003c\/td\u003e\n\u003ctd\u003e0.25 oversize piston ring set; alternate aftermarket reference\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e13011-HM7-004\u003c\/td\u003e\n\u003ctd\u003eRIKEN\u003c\/td\u003e\n\u003ctd\u003eStandard (0.00) ring set; related OEM reference for comparison\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eCross-reference notes reflect common aftermarket mappings to OEM Honda part numbers used for TRX400FW Foreman 4x4 (1995-2003).\u003c\/p\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cp\u003eEach kit is designed for one cylinder and includes the essential rings to restore proper sealing on the TRX400FW engine:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cb\u003eTop Compression Ring\u003c\/b\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cb\u003eSecond Compression Ring\u003c\/b\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cb\u003eOil Ring\u003c\/b\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eNote: Related components such as pistons, circlips, or wrist pins are not included.\u003c\/em\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 Precisely matched to Honda TRX400FW Foreman 4x4 engines from 1995–2003 for straightforward installation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eOEM Cross-Reference:\u003c\/b\u003e Includes cross-reference to OEM-equivalent numbers (13021-HM7-003 and 13021-HM7-004) for fit verification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePremium Materials:\u003c\/b\u003e Durable steel alloy with chrome-plated compression rings designed to resist wear and maintain sealing over time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAccurate Oversize:\u003c\/b\u003e 0.25 mm oversize restores correct bore clearance after wear, helping regain compression and control oil consumption.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSolid Value:\u003c\/b\u003e A rebuild-quality option that offers genuine rebuild performance without OEM-price premiums.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eReliability in Harsh Conditions:\u003c\/b\u003e Built to stand up to trail, farm, and weekend-warrior environments where dust, heat, and load are constant.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation Notes:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eMeasure bore after removing old rings:\u003c\/b\u003e Confirm standard bore is 86.00 mm; plan for a 0.25 mm oversize if you’re choosing the 86.25 mm configuration.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eInstall in the correct ring order:\u003c\/b\u003e Top compression ring, second compression ring, then oil ring per cylinder.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eCheck ring end gaps and seating:\u003c\/b\u003e Follow the service manual’s specifications for ring gap spacing in the bore; avoid gaps aligning across rings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eLightly lubricate rings and bore:\u003c\/b\u003e Apply a thin coat of clean engine oil to rings and the cylinder wall before assembly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eEnsure proper piston orientation:\u003c\/b\u003e If using a piston-with-rings kit, verify any orientation marks on the piston crown point toward the exhaust side.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eBreak-in procedure:\u003c\/b\u003e After assembly, run a light-to-moderate load break-in to seat rings properly before returning to full power.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy Upgrade?\u003c\/h3\u003e\n\u003cp\u003eRunning a worn or undersized set of rings on a TRX400FW can lead to persistent compression loss, increased blow-by, higher oil consumption, and degraded throttle response. Replacing with an accurate 0.25 oversize kit restores proper bore clearance and sealing, delivering reliable compression and calmer oil control for dependable performance in tough trail and farm conditions.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"ATV City","offers":[{"title":"Default Title","offer_id":57319261733238,"sku":"192.04502","price":17.08,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0971\/0302\/0406\/files\/pistonring_dc7689a5-669f-4d2e-bd9d-d6f4ba18c005.png?v=1774886192","url":"https:\/\/dgtagri.co.uk\/products\/piston-ring-kit-honda-trx-400-os-0-25-1995-2003","provider":"DGT Agri","version":"1.0","type":"link"}