Honda 400EX 426cc Big Bore Kit + Hotcam Valves TRX400X 99–14

SKU 256110437057

🏁 Honda 400EX / 400X 426cc Big Bore Top End Kit – Fits All 1999–2014 Models

Stage 2 Hotcam | Valves + Springs | No Head or Case Mods Needed

Boost your Honda 400EX or 400X into a true trail beast with this complete 426cc top end big bore kit. Everything’s included to upgrade your top end — no machining required.

📦 What’s Included:

• 88mm big bore cylinder

• Wiseco or Wossner forged piston (we send what's most available, Usually Wiseco)

• Hi-temp piston rings

• Chrome wrist pin & circlips

• Cometic top-end gasket kit

• Hotcams Stage 2 camshaft

• Camshaft bearings

• Talon TITANIUM cylinder stud kit

• Heavy-duty timing chain

• Hardened steel intake & exhaust valves

• Valve springs and retainers

• Valve stem seals

• Stickers for the finishing touch

💥 Key Features & Benefits:

• 🔩 +3mm overbore = 426cc displacement

• 🛠️ No head or case mods required – completely bolt-on

• 💪 Titanium stud kit resists stretching & improves reliability

• 🧊 Runs strong on pump or race gas

• 🏁 Stage 2 Hotcam offers serious gains across the mid & top RPM range

• 🧩 Complete valve upgrade with hardened valves, springs, retainers & seals

✅ Compatibility:

Fits all Honda Sportrax 400EX and TRX400X models from 1999 to 2014:

• 1999–2008 TRX400EX

• 2009–2014 TRX400X

🛡️ Warranty Information:

All components are brand new in original packaging. Manufacturer warranties apply. We strongly recommend professional installation by an experienced mechanic. Warranty does not cover failure due to improper installation, tuning, break-in, or abuse. Returns and warranty claims require parts be sent back for inspection.