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Honda 400EX Big Bore Kit

VS $387.22 MSRP
$320.90 SAVINGS

In stock

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    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
HondaATVXR400R A1996
HondaATVXR400R A1997
HondaATVXR400R A1998
HondaATVXR400R A/A1998
HondaATVXR400R AC1998
HondaATVXR400R AC/A1998
HondaATVTRX400EX A1999
HondaATVXR400R A1999
HondaATVXR400R AC1999
HondaATVTRX400EX A2000
HondaATVXR400R A2000
HondaATVXR400R AC2000
HondaATVTRX400EX A2001
HondaATVXR400R A2001
HondaATVXR400R AC2001
HondaATVTRX400EX A2002
HondaATVXR400R A2002
HondaATVXR400R AC2002
HondaATVTRX400EX A2003
HondaATVXR400R A2003
HondaATVXR400R A/A2003
HondaATVXR400R AC2003
HondaATVXR400R AC/A2003
HondaATVTRX400EX A2004
HondaATVXR400R A2004
HondaATVXR400R A/A2004
HondaATVXR400R A/B2004
HondaATVXR400R A/C2004
HondaATVXR400R AC2004
HondaATVXR400R AC/A2004
HondaATVXR400R AC/B2004
HondaATVXR400R AC/C2004
HondaATVTRX400EX A2005
HondaATVTRX400EX A2006
HondaATVTRX400EX A2007
HondaMotorcycleXR400R A1996
HondaMotorcycleXR400R A1997
HondaMotorcycleXR400R A1998
HondaMotorcycleXR400R A/A1998
HondaMotorcycleXR400R AC1998
HondaMotorcycleXR400R AC/A1998
HondaMotorcycleTRX400EX A1999
HondaMotorcycleXR400R A1999
HondaMotorcycleXR400R AC1999
HondaMotorcycleTRX400EX A2000
HondaMotorcycleXR400R A2000
HondaMotorcycleXR400R AC2000
HondaMotorcycleTRX400EX A2001
HondaMotorcycleXR400R A2001
HondaMotorcycleXR400R AC2001
HondaMotorcycleTRX400EX A2002
HondaMotorcycleXR400R A2002
HondaMotorcycleXR400R AC2002
HondaMotorcycleTRX400EX A2003
HondaMotorcycleXR400R A2003
HondaMotorcycleXR400R A/A2003
HondaMotorcycleXR400R AC2003
HondaMotorcycleXR400R AC/A2003
HondaMotorcycleTRX400EX A2004
HondaMotorcycleXR400R A2004
HondaMotorcycleXR400R A/A2004
HondaMotorcycleXR400R A/B2004
HondaMotorcycleXR400R A/C2004
HondaMotorcycleXR400R AC2004
HondaMotorcycleXR400R AC/A2004
HondaMotorcycleXR400R AC/B2004
HondaMotorcycleXR400R AC/C2004
HondaMotorcycleTRX400EX A2005
HondaMotorcycleTRX400EX A2006
HondaMotorcycleTRX400EX A2007
HondaATVTRX400EX A2008
HondaATVTRX400X 3A2009
HondaATVTRX400X A2009
HondaATVTRX400X A2012
HondaATVTRX400X AC2013
HondaATVTRX400X AC2014

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.


Customer Reviews (35)

Review by tmckinney1967 
fast shipping thanks! (Posted on 3/7/2016)
Review by adamverrier96 
Wow! Crazy fast shipping! Awesome parts! (Posted on 3/2/2016)
Review by patsyreel 
A+++++ Seller, Smooth Transaction, Fast shipping! (Posted on 2/26/2016)
Review by goat315 
good part, shipped fast, AAA+++ (Posted on 2/25/2016)
Review by lbougiedirtbike 
Very fast shiping (Posted on 2/24/2016)
Review by sykes2011charles 
Would have liked the kit to have the heavy duty head bolts in the package. (Posted on 2/20/2016)
Review by bgreen3204 
best price, great item, fast shipper (Posted on 2/18/2016)
Review by joegill24 
Got here early (Posted on 2/5/2016)
Review by pbutt1023 
Works great (Posted on 1/31/2016)
Review by bgreen3204 
best price, great item, fast shipper (Posted on 1/30/2016)
Review by yat1833yas-us 
Its exactly what it said it was.and it works. (Posted on 1/27/2016)
Review by schorte85 
5s (Posted on 1/14/2016)
Review by chevyboyz920 
Great packaging, vary fast shipping A+++ (Posted on 1/12/2016)
Review by forced-racing 
Item as described and shipped promptly. Thx (Posted on 1/10/2016)
Review by patsyreel 
A+++++ Seller, Smooth Transaction, Fast shipping! (Posted on 1/4/2016)
Review by sportsandbeond2012 
Super fast will do business again (Posted on 12/24/2015)
Review by mrsfury80 
Very fast shipping!! Item just as described!! (Posted on 12/17/2015)
Review by highway12motorsports 
A+++ thank you!! (Posted on 12/2/2015)
Review by raptorslow54 
Fast Shipping !! Recommended Seller !!!! (Posted on 11/27/2015)
Review by vince.adria 
(Posted on 11/6/2015)
Review by josensalas832011 
Thanks (Posted on 11/2/2015)
Review by kmp1_17_1990 
Shipped super fast! Thank you! (Posted on 10/31/2015)
Review by foxboy_tyson_15 
nice kit (Posted on 10/25/2015)
Review by drpimp 
Good (Posted on 10/23/2015)
Review by lfoxworth2012 
Everything was perfect , thank you (Posted on 10/8/2015)
Review by schorte85 
5s (Posted on 9/27/2015)
Review by flyonthewalltackle 
VERY FAST! (Posted on 9/27/2015)
Review by reyes8403 
Just got thanks (Posted on 9/22/2015)
Review by marty3670 
super fast shipper (Posted on 9/18/2015)
Review by kmp1_17_1990 
Shipped super fast! Thank you! (Posted on 9/13/2015)
Review by shotgun2brll 
Great Seller and Communications. will do business with them anytime (Posted on 9/12/2015)
Review by marty3670 
super fast shipper (Posted on 8/22/2015)
Review by el_monstro_86 
Great product thanks !!! (Posted on 8/14/2015)
Review by tmckinney1967 
fast shipping thanks! (Posted on 8/12/2015)
Review by srm_italia 
Perfect seller! Incredible seller ! Thanks so much (Posted on 8/2/2015)

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