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Honda 400EX Big Bore Kit

VS $387.22 MSRP
$320.90 SAVINGS

In stock

    Quick Look

  • A complete 440cc big bore cylinder kit
  • 89 mm x 70 mm bore and stroke
  • 10:1 piston compression
  • 440cc displacement
  • Improved casting design with larger cylinder sleeve
  • Moly-coated performance piston kit
  • This item includes: Cylinder, Piston, Piston Rings, Wristpin, Circlips (2)
12100-KCY-670, 12191-KCY-672
13011-KCY-670, 90601-KA5-000
13101-KCY-670, 13111-KCY-670
91301-428-003, 12251-HN1-003
12100-HN1-A70, 12191-HN1-A71
Fits My Vehicle?
This Cylinder Kit fits
Make Type Model Year
Honda ATV XR400R A 1996
Honda ATV XR400R A 1997
Honda ATV XR400R A 1998
Honda ATV XR400R A/A 1998
Honda ATV XR400R AC 1998
Honda ATV XR400R AC/A 1998
Honda ATV TRX400EX A 1999
Honda ATV XR400R A 1999
Honda ATV XR400R AC 1999
Honda ATV TRX400EX A 2000
Honda ATV XR400R A 2000
Honda ATV XR400R AC 2000
Honda ATV TRX400EX A 2001
Honda ATV XR400R A 2001
Honda ATV XR400R AC 2001
Honda ATV TRX400EX A 2002
Honda ATV XR400R A 2002
Honda ATV XR400R AC 2002
Honda ATV TRX400EX A 2003
Honda ATV XR400R A 2003
Honda ATV XR400R A/A 2003
Honda ATV XR400R AC 2003
Honda ATV XR400R AC/A 2003
Honda ATV TRX400EX A 2004
Honda ATV XR400R A 2004
Honda ATV XR400R A/A 2004
Honda ATV XR400R A/B 2004
Honda ATV XR400R A/C 2004
Honda ATV XR400R AC 2004
Honda ATV XR400R AC/A 2004
Honda ATV XR400R AC/B 2004
Honda ATV XR400R AC/C 2004
Honda ATV TRX400EX A 2005
Honda ATV TRX400EX A 2006
Honda ATV TRX400EX A 2007
Honda Motorcycle XR400R A 1996
Honda Motorcycle XR400R A 1997
Honda Motorcycle XR400R A 1998
Honda Motorcycle XR400R A/A 1998
Honda Motorcycle XR400R AC 1998
Honda Motorcycle XR400R AC/A 1998
Honda Motorcycle TRX400EX A 1999
Honda Motorcycle XR400R A 1999
Honda Motorcycle XR400R AC 1999
Honda Motorcycle TRX400EX A 2000
Honda Motorcycle XR400R A 2000
Honda Motorcycle XR400R AC 2000
Honda Motorcycle TRX400EX A 2001
Honda Motorcycle XR400R A 2001
Honda Motorcycle XR400R AC 2001
Honda Motorcycle TRX400EX A 2002
Honda Motorcycle XR400R A 2002
Honda Motorcycle XR400R AC 2002
Honda Motorcycle TRX400EX A 2003
Honda Motorcycle XR400R A 2003
Honda Motorcycle XR400R A/A 2003
Honda Motorcycle XR400R AC 2003
Honda Motorcycle XR400R AC/A 2003
Honda Motorcycle TRX400EX A 2004
Honda Motorcycle XR400R A 2004
Honda Motorcycle XR400R A/A 2004
Honda Motorcycle XR400R A/B 2004
Honda Motorcycle XR400R A/C 2004
Honda Motorcycle XR400R AC 2004
Honda Motorcycle XR400R AC/A 2004
Honda Motorcycle XR400R AC/B 2004
Honda Motorcycle XR400R AC/C 2004
Honda Motorcycle TRX400EX A 2005
Honda Motorcycle TRX400EX A 2006
Honda Motorcycle TRX400EX A 2007
Honda ATV TRX400EX A 2008
Honda ATV TRX400X 3A 2009
Honda ATV TRX400X A 2009
Honda ATV TRX400X A 2012
Honda ATV TRX400X AC 2013
Honda ATV TRX400X AC 2014

This Big Bore Kit Fits: Honda XR400R (1996-2004), TRX400X (2009, 2012-2014) and TRX400EX (1999-2008)

The 400EX Big Bore Kit is designed  to help get more power out of your engine:

  • This kit ups the stock displacement from 397cc to 440cc by increasing the cylinder bore from 85 mm to 89 mm. 
  • The cylinder is the product of improved casting design that has a larger cylinder sleeve. This thicker sleeve supports improved reliability over factory cylinders that have been over bored because it prevents your cylinder from warping at higher temperatures.
  • The moly-coated performance piston kit increases the stock compression from 9.1:1 to 10:1. 
  • The custom-designed piston also helps increase power in the low to mid rpms.
  • Includes a big bore cylinder, piston, piston ring set, wristpin, circlips, head gasket, base gasket and O-ring. 

The 400EX Big Bore Cylinder Kit also includes a high-performance top end gasket kit to give your engine more reliability and longevity.

All of the parts included are direct replacement parts for easy, hassle-free installation with no modifications or adjustments needed. Everything has been engineered and tested to exceed original equipment standards and performance.

Crave more power from your TRX400EX? Dying for more acceleration? Dreaming of ripping through dunes and tearing through trails? 

This big bore kit has been designed with performance in mind: from the cylinder to the piston, right down to the gaskets. In addition, We offer top-notch customer service, fast shipping, and quality parts at reasonable prices.

Not looking for a big bore kit? Check out our standard sized cylinder kit here: Honda TRX400EX Cylinder Kit by Niche. Not looking to rebuild the whole top end? Purchase just the big bore cylinder here.

All ground shipments are sent FREE within mainland USA . Read more...

You may Return or Exchange any part(s) back to us within 45 days from the payment date. See conditions.


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