Description

Rebuild Your Honda TRX400EX / 400EX Engine

The Honda TRX400EX has earned its reputation as one of the most dependable sport ATVs ever built. Whether you ride wooded trails, explore dunes, or enjoy weekends at your favorite riding area, a worn engine can quickly cut your day short. Our Build Core engine rebuild service restores your original engine so you can keep riding the ATV you already know and enjoy.

Every rebuild begins with your rebuildable engine core. After it arrives at REV6, we inspect every major component, complete the required machine work, rebuild the engine to specification, and perform a final quality inspection before it ships back to you.

Engine Rebuild Overview

• Service: Build Core Engine Rebuild
• Fits: Honda TRX400EX / 400EX (1999–2014)
• Core Required: Yes
• Warranty: 1-Year No-Fault Warranty Included
• Optional Coverage: Upgrade to our 2-Year No-Fault Warranty
• Financing: Available
• Shipping: Nationwide with tracking information provided
• Typical Turnaround: Approximately two weeks after your engine arrives, depending on its condition and parts availability

What’s Completed During the Rebuild

• Complete engine teardown, cleaning, and inspection
• Cylinder head inspected and resurfaced as needed
• Camshaft lobes and journals cleaned and polished
• Cylinder bored and honed to specification
• New moly-coated piston, rings, wrist pin, and circlips
• Crankshaft inspected and rebuilt as needed
• Transmission gearbox and shift assembly inspected
• Clutch assembly inspected
• Bottom-end bearings inspected
• Oil pump inspected and rebuilt as needed
• Engine cases inspected for cracks, journal wear, and damage
• Final quality inspection before shipment

How the Build Core Process Works

This service requires your rebuildable Honda TRX400EX engine core. After your order is placed, our team will walk you through the shipping process and answer any questions before your engine is sent to REV6.

Every engine is different. If our inspection uncovers damaged or unusable components outside the standard rebuild process, we’ll review your options and obtain approval before completing any additional work.

Warranty & Financing Options

Every rebuilt Honda TRX400EX engine is backed by our 1-Year No-Fault Warranty. For riders who want additional protection, an optional 2-Year No-Fault Warranty is also available.

For complete coverage details, visit our Warranty Policy. Flexible payment options are available through our Financing page.

Shopping for Parts Instead?

If you’re rebuilding your own engine, browse our Honda ATV parts catalog for replacement components and rebuild kits. You can also compare available rebuild options with our Engine Rebuild Kit Guide.

Let’s Bring Your TRX400EX Back to Life

When you’re ready, place your order and send us your rebuildable engine core. We’ll handle the inspection, rebuilding, and final quality checks before returning your engine ready for installation.

Eligible veterans and active-duty military personnel can receive exclusive REV6 discounts. Ask our team for details before placing your order.