TRX400EX TRX 400EX 89mm 440cc Big Bore Race Gas Hi-Comp 12.5 Piston Top End Kit
Upgrade your Honda TRX400EX with a complete 440cc big bore kit featuring an 89mm cylinder, forged 12.5:1 piston, Cometic gaskets, titanium studs, and timing chain. ,4667M08900, 8604D400, 247612, M2033, 1043-2, M2008, M2003, M2001,4606M08700,12100-KCY-670, 4606M08500, C7826, 71016-4, 12191-KCY-673, 30-33750, 13011-KCY-670, 90601-KA5-000, 13103-KCY-670, 13111-KCY-670, 12251-HN1-003, 12209-KL4-005, C7825, 808894, 822278, 4040, 4606M08700, C7826, H0402027S, 4606M08800, 4667M08900, 808829, M2033, 8604DA, 192258099805
BPRATV TRX400EX 440cc Big Bore Race Gas 12.5:1 Complete Top End Rebuild Kit Honda TRX400EX 400X XR400R
📖 Product Description
Take your Honda sport ATV to the next level with the BPRATV TRX400EX 440cc Big Bore Race Gas Top End Kit. Designed for riders who demand maximum horsepower and reliability, this complete performance package upgrades your engine to an 89mm (440cc) configuration using a premium high-compression forged piston and precision-machined big bore cylinder. Built specifically for race gas applications, this kit delivers stronger acceleration, increased torque, and improved throttle response while maintaining exceptional durability for aggressive trail and track riding.
Featuring premium components from industry-leading manufacturers, this complete top-end rebuild kit is engineered for a straightforward installation without requiring case or cylinder head machining. Whether you're refreshing a worn engine or building a competitive race machine, this kit provides the performance and reliability serious riders expect.
🔥 Key Features & Benefits
- 89mm 440cc Big Bore Cylinder increases displacement for substantially more horsepower and torque.
- 12.5:1 Forged Wiseco or JE Piston engineered for race gas performance.
- Nitride-coated piston rings provide superior sealing, durability, and reduced wear.
- Chrome wrist pin and circlips included for dependable high-RPM operation.
- Talon Titanium cylinder head stud kit offers exceptional clamping force with a lifetime warranty.
- Cometic MLS Big Bore gasket kit ensures reliable sealing under extreme cylinder pressures.
- Heavy-duty timing chain conversion provides accurate valve timing and improved longevity.
- Direct-fit design requires no crankcase or cylinder head modifications.
📦 Product Contents
- 89mm BPRATV big bore cylinder
- 12.5:1 forged Wiseco or JE piston
- Nitride-coated piston ring set
- Chrome wrist pin
- Wrist pin circlips
- Talon Titanium cylinder head stud kit
- Cometic complete top end gasket kit
- MLS big bore head gasket
- Heavy-duty timing chain conversion cam chain
✅ Compatibility
Designed to fit the following Honda models:
- Honda TRX400EX
- Honda TRX400X
- Honda XR400R
❓ FAQ
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Q: Does this kit require race fuel?
A: Yes. The included 12.5:1 compression piston is designed for race gas applications only.
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Q: Is machining required to install this kit?
A: No. This kit is designed as a direct-fit upgrade with no cylinder head or crankcase modifications required.
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Q: What displacement does this kit produce?
A: The 89mm cylinder increases engine displacement to approximately 440cc.
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Q: Is everything needed for the top-end rebuild included?
A: Yes. The kit includes the cylinder, forged piston assembly, rings, wrist pin, circlips, titanium head studs, Cometic gasket kit with MLS head gasket, and heavy-duty timing chain.
🌟 Why Buy from BPRATV
At BPRATV, our promise is unwavering: The Best Parts. The Best Performance. The Best Price. We specialize in high-performance powersports components trusted by riders and builders who demand reliability and results. Every part is carefully selected for precision, durability, and real-world performance. Trust BPRATV to keep your Honda TRX400EX, TRX400X, or XR400R running at its best, every single time.
Upgrade your Honda 400 with legendary 440cc race-winning performance--order your complete BPRATV Big Bore Kit today!
BPRATV - The Best Parts. The Best Performance. The Best Price.
BRAPPPPPPPPPP!
© BPRATV LLC
Due to the nature of high performance and racing applications, BPRATV LLC components are sold without express warranty or any implied warranty of merchantability or fitness for a specific purpose. BPRATV LLC shall not, under any circumstances, be liable for any specific, incidental or consequential damages, including, but not limited to, damage, or loss of property or equipment, loss of profits or revenue(s), cost of purchased or replacement goods, or claims of customers of the purpose, which may arise and/or shall result from sale, installation or use of these parts. Installation of these parts may void vehicle manufacturers warranty coverage and/or may cause the vehicle to be illegal in some locations.
This product is exempt from the emission standards and related requirements of 40 C.F.R. §1051 as provided by 40 C.F.R. §1051.620, and California law. This product is sold only for use in connection with EPA-certified, purpose-built, nonroad vehicles used solely for closed-course, nonroad competition/racing.
