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Honda 400EX 400X 89mm Rebuild Kit Top Bottom Big Bore Motor Engine Assembly 440c


Compatible Vehicles
Submodel Year Make Model
TRX400EX 2x4 2008 Honda Sportrax 400
TRX400EX 2x4 2007 Honda Sportrax 400
TRX400EX 2x4 2006 Honda Sportrax 400
TRX400EX 2x4 2005 Honda Sportrax 400
2x4 2014 Honda TRX400X
2x4 2013 Honda TRX400X
2x4 2012 Honda TRX400X
2x4 2011 Honda TRX400X
2x4 2010 Honda TRX400X
2x4 2009 Honda TRX400X
  • Aftermarket 89mm big bore cylinder
  • 89mm big bore Wiseco JE or CP forged piston*
  • Nitrite coated piston rings
  • Chrome wristpin
  • Circlips
  • Hotrods OEM replacement crankshaft with rod
  • Main bearings
  • Crank balancer bearings
  • Transmission bearings
  • Complete gasket kit
  • MLS head gasket
  • Oil seal kit
  • Valve stem seals
  • Clutch kit
  • Timing chain
  • NGK spark plug
  • K&N oil filter
  • Maxlock head stud kit - LIFETIME WARRANTY*
  • All parts are brand new
  • 1 year warranty*

We are BPRATV.  Feel free to contact us or visit us at our Upland, CA location.  Our store hours are 7am to 4pm, Monday to Friday, PST


If you work on bikes for a living, be it full time or on the side, contact us about setting up a dealer account and save on everything we sell!

Payments:  We accept all forms of traditional and online payment methods available – Cash, MC, AMEX, VISA, DISC, Paypal, Venmo, Cashapp, among others.  Payment can be made online or over the phone.  PRICES ARE SUBJECT TO CHANGE AND LISTINGS MAY BE REVISED AT ANY TIME WITHOUT NOTICE.

**Products we sell: We sell brand name parts that perform well, last, and are from companies you have grown to trust, and we stock the same parts from different manufacturers so that when back orders happen we have a part that is of equal value to send, preventing long wait times. This would be the ONLY reason your order might be slightly different when it arrives.  If you want a certain brand part just ask (if part is back ordered this may cause a delay on your order).

Returns: Please check your order completely when you receive it and contact us if there is an issue.  99% of problems can be easily solved without returning the entire order.  We accept returns within the first 30 days and may be subject to a restocking fee.  Orders must be sent back 100% complete and all parts must be brand new, never installed, in the original packaging to receive a refund for them.  Once items have been modified, installed, or used in any way they are not eligible for return.  It is the buyer’s responsibility to ensure returned parts arrive to us in the same condition they were when they left our facility.

*Warranty: We stand behind all parts we sell 100%.  If after installation there is an issue contact us for a warranty return.  This product is NOT DIY.  Over 99% of people in the world are not qualified to build an engine, and it is the responsibility of the person installing and tuning the parts to make sure they work properly.  We ALWAYS STRONGLY recommend parts be installed by a qualified, experienced mechanic.  STUD WARRANTY: If for any reason a stud fails during use, not installation, we will send a new, complete stud kit.  No other parts or any labor are included, and it cannot be converted to a refund or discount on any order.  FOR ALL PARTS WE SELL the warranty does not cover failure that is a result of improper installation, tuning, break in, or misuse.  For any warranty to be considered the part(s) in question must first be sent back to us for inspection.  We do not warranty parts based on phone calls, emails, photos, what you read online, or another mechanic's assessment alone.

Feedback: Positive feedback is greatly appreciated.  We have changed the way we do business in response to customer concerns and receiving positive feedback when an order goes the way it is supposed to is a huge help.  If you do not feel we deserve positive feedback just contact us and we will do what is needed to help you feel as "positive" as possible about your experience.  Also, we want information from customers when their experience is less than desirable so we know what areas need improvement the most.  Please work with us and we will ALWAYS work with you.