Top End Gasket Kit for Honda TRX450 S/ES/FE/FM Foreman 450, 1998–2004. This aftermarket replacement Top End Gasket Kit includes all gaskets and seals necessary for a complete top-end rebuild, restoring compression, sealing integrity, and engine reliability after cylinder work. Manufactured by Aftermarket Replacement, this kit is designed to deliver dependable performance across all TRX450 Foreman variants.

Comprehensive Vehicle Fitment

*Notes: This kit covers the top-end seal components for the listed TRX450 Foreman models and years. Cross-reference OEM numbers when performing a rebuild to ensure correct compatibility with your specific engine revision. Fitment details are based on commonly referenced OEM cross references for Honda TRX450 S/ES/FE/FM Foreman 450 4x4 (1998–2004).*

Product Specifications

OEM Cross-Reference Information

*OEM cross-reference numbers are provided for reference purposes only. These part numbers are confirmed for 1998-2004 TRX450 Foreman models through multiple aftermarket and OEM sources . Always verify fitment using your machine's exact model, year, and original part number before ordering.*

What's Included

Based on standard top-end gasket kits for the TRX450 engine, this kit typically includes:

• Cylinder head gasket (replaces OEM 12251-HN0-A01)

• Cylinder base gasket (replaces OEM 12191-HM7-013)

• Cylinder head cover gasket (replaces OEM 12315-HM7-005)

• Exhaust gasket(s) (replaces OEM 18291-MN4-920)

• Intake gaskets

• Valve stem seals

• Related O-rings and seals as required for complete top-end sealing

Note: This is a top-end gasket kit. For complete engine rebuilding, additional components such as pistons, rings, and wrist pins may be required and are available separately from aftermarket suppliers.

Why Choose This Aftermarket Top End Gasket Kit?

• Direct-Fit Compatibility: Precision-engineered for Honda TRX450S (1998-2001), TRX450ES (1998-2001), TRX450FE (2002-2004), and TRX450FM (2002-2004) Foreman models .

• OEM Cross-Reference: Cross-references genuine Honda part numbers 12100-HN0-A00, 12251-HN0-A01, 12191-HM7-013, 13101-HN0-A00, 13010-HN0-A02, 13111-HN0-A00, and 13112-MAT-000 for confident replacement .

• Proven Aftermarket Support: Multiple respected aftermarket brands manufacture compatible gasket kits:

  • Pro-X Racing Parts offers top-end gasket kits (Part No. 35.1498) specifically for 1998-2004 TRX450FE/FM models, designed for precise sealing, maximum durability, and optimal engine performance .

  • Outlaw Racing provides complete engine gasket kits (OR4211) for 1998-2004 TRX450 models, constructed from materials such as Stainless Steel, Fluoroviton and Teflon to exceed OEM specs .

  • NICHE supplies top-end rebuild kits (519-KGS2251K, MK1003420) with quality and performance guaranteed .

• Restores Compression: New head and base gaskets ensure proper cylinder sealing for optimal engine performance.

• Prevents Leaks: Complete sealing kit prevents oil seepage and maintains clean engine operation.

Installation Notes:

• Ensure all mating surfaces are clean and free from old gasket material before installation.

• Follow manufacturer torque specifications and tightening sequences for cylinder head bolts.

• Use new gaskets only—do not reuse old gaskets once removed.

• Check valve clearance after head installation and adjust if necessary.

• After installation, run the engine and check for any signs of leaks.

• Verify your specific model and year before ordering, as the TRX450 was produced in multiple 4x4 configurations across 1998-2004 .

Why Upgrade?
Worn or damaged gaskets can cause compression loss, oil leaks, and contamination—leading to poor performance and potential engine damage. Restore your Honda TRX450 Foreman engine's sealing integrity with this quality aftermarket top end gasket set, designed to keep you working and riding with confidence.

Order your top end gasket kit today and get back on the trail with confidence.