Honda 400EX / XR400R Race-Ported Head – +1mm Valves, Complete

🔥 Race-Ported Cylinder Head Assembly – Honda TRX400EX / 400X / XR400R
Complete, Fully Assembled | +1mm Valves | Machined & Ready to Perform

Give your Honda 400EX or XR400R the airflow and durability it deserves. This fully built, race-ported cylinder head is designed for riders pushing their machines hard — whether on the dunes, trails, or the track. Includes +1mm oversized stainless valves and all new internals.

✅ Fits all years of TRX400EX, TRX400X, and XR400R
✅ No head or cylinder modifications required to install
✅ Includes all new hardware – completely assembled
✅ Allow 4–6 weeks for precision machining & assembly

📦 What’s Included:

• 🧱 New Aftermarket Cylinder Head + Valve Cover

• 🛠️ Full Race Port and Polish

• 🔧 Valve Guides Cut & Pocket Ported for +1mm Valves

• ⚙️ Kibblewhite +1mm Black Diamond Intake & Exhaust Valves

• 🔩 Kibblewhite Performance Valve Spring Kit

• 🛡️ Kibblewhite Viton Valve Stem Seals

• 🔁 Rocker Arms + Rocker Shafts

• 🔩 Valve Keepers, Washers, and All Required Hardware

• 🎁 All Parts Brand New + 1-Year Warranty*

⚙️ Key Features:

• 🔧 Precision-Machined and Fully Assembled

• 🔥 +1mm Oversized Valves for Increased Flow and Power

• 💥 Full Race Port + Pocket Porting – Ideal for built motors

• 🧰 Ready to Drop In – No additional work needed

• 🛡️ Premium Kibblewhite Valvetrain Components

✅ Fitment Compatibility:

🕒 Lead Time for Machine Work:

Please allow 4–6 weeks for all machining and porting services. Each head is custom finished and assembled to order for optimal performance.

📦 Shipping Time:

Ships after machining is complete (4–6 weeks). Tracking provided upon shipment.

💬 Customer Support:

Available Monday–Friday, 7 AM to 4 PM PST
Live store chat available 24/7