Honda TRX400EX/400X 87mm Big Bore Rebuild Kit | 1999–2004 or 2005–2013 Variants

Honda TRX400EX/400X 87mm Big Bore Rebuild Kit | 1999–2004 or 2005–2013 Variants

Regular price$2,294.00
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1999-2004
1999-2004
2005-2013
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Honda TRX400EX / TRX400X (2005–2014) — 87 mm Big Bore Complete Engine & Cylinder Head Rebuild Kit

🛠️ Description

Build a stronger, pump-gas 400EX/400X with this complete 87 mm big bore package. Includes new cylinder and head, forged piston, Stage 2 cam, HD bottom-end components, and all gaskets and seals. Bolt-on design with no case or head machining required.

✅ What’s Included

  • Works on all 2005+ Honda 400EX and 400X models

  • 87 mm cylinder

  • 87 mm big bore Wiseco or Wossner forged piston

  • Nitride-coated piston rings (aka nitrite-coated)

  • Chrome wrist pin

  • Circlips

  • Cylinder head with valve cover

  • HD crankshaft assembly with rod

  • Crank bearings

  • Crank balancer bearings

  • Transmission bearings

  • Clutch bearings

  • Shift cam bearings

  • Camshaft bearings

  • Stage 2 replacement camshaft

  • HD cam chain

  • Cam chain guides

  • Black billet cam chain tensioner

  • Complete gasket kit

  • Cometic big bore MLS head gasket

  • Seal kit

  • Clutch kit

  • Talon TITANIUM cylinder head stud kit — Lifetime warranty*

  • NGK spark plug

  • No case or head mods required

  • Runs on pump or race gas

  • 1-year warranty on all new parts*

📦 Fitment

  • Honda TRX400EX: 2005–2008

  • Honda TRX400X: 2009–2014
    (Not intended for 1999–2004 models.)

🛡️ Warranty Info

  • All parts are new and carry a 1-year limited warranty from the original manufacturers.

  • Talon titanium stud kit includes a lifetime warranty.

  • Returns accepted on new, uninstalled items only. Professional installation recommended.

🔑 Key Features

  • ~416 cc displacement using 87 mm bore

  • Forged piston for strength and heat control

  • Stage 2 cam for midrange pull and stronger top end

  • HD crank and bearings for durability

  • MLS head gasket and titanium studs for superior sealing

  • Runs on 91-octane pump gas with proper jetting and tune

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