Wiseco Big Bore 440 Kit

Choose a vehicle:

User Tip: If you're unsure of your vehicle type, you may skip the machine type selection box.

» Log in to use your Rider Profile Machines
Wiseco Big Bore 440 Kit
  • View Larger
  • Video

Wiseco Big Bore 440 Kit

Our Price: $257.14$276.24

View Product Details

Select type, year, make and model above

Live Help
  • "Customer service is priority #1 at Rocky Mountain ATV/MC. We value our customers and strive to be the best shopping experience- when you buy from us, you are buying lifetime service."

    -Dan Thomas, CEO and Founder

  • Returns

    We take pride in offering no hassle returns. In the event of a return, please call, email or chat with us to receive a solution to the problem. For apparel that doesn't fit quite right, Click here to see our Fit Guaranteed Program.

  • Warranties

    We will stand behind all products we sell with regards to manufacturing defects in workmanship and material. Most products are limited to the manufacturer's warranty. However, we will do everything in our power to take care of the problem.

  • Have questions?

    Live Help (Leave email if after hours)
    Email: sales@rockymountainatv.com
    Call us: 1 800 336-5437
    7am-7pm Mon-Fri 8am-4pm Sat (Mountain Standard Time)

Additional Videos

How to - check piston ring end gap

How to - rebuild the top end on a motorcycle or atv (Part 2)

How To - Hone A Cylinder

How to - rebuild the top end on a motorcycle or atv (Part 1)

RM YouTube Channel

Details

  • This kit includes all the necessary parts needed to increase your engines displacement to the largest reliable engine size.
  • This kit has been proven through the rigors of competition to be reliable and offer an impressive power increase .
  • Kit includes piston kit, big bore sleeve as well as the head and base gasket .
  • Engine displacement is increased to 440cc .
  • Professional bore and sleeve installation is required.

Wiseco Big Bore 440 Kit Reviews

Each review submitted enters you into a
$100 gift card monthly drawing and a
$500 gift card quarterly drawing!
 
4.8 / 5.0
6 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
5
1
0
0
0
Best mod ever
This was buy far the best upgrade I did to this quad. Great fit.

Machine this part was bought for: 2002 HONDA TRX 400EX
January 13, 2015
95610, CA, US
Age: 25-44
Gender:
Male
RMATV customer service and product performance
Very dissappointed in the knowledge of the RM sales team. They told me that all I would have to do (to my 2004 400ex) was press out the old sleeve and press the new one in, however that was not the case. The machine shop had to press out the old one, bore and counter bore the cylinder in order to press the new sleeve in, then after getting the cylinder back I went to put it all together just to find out that the sleeve had to be bored to the piston also. Wasn't very costly to have done ( about $120) but would've been nice to have known all this from the start. Wisecos 440 big bore kit is the bomb tho, along with hot cams stage 2 cam and a dyno jet jet kit my quad is wicked fast.
June 26, 2011
TN
I would definitely recommend it
I put this kit in my 04 XR 400. It gave it more power through out the rpm range. But way down low was where I really noticed an improvement. I can really lug the motor down through extreme technical sections on the trail now and with out having to slip the clutch. I noticed I could even run a gear higher which settled down the suspension which in turn made me able to go faster. I did have to use a ring compressor to install the piston though.
July 29, 2010
NV
KFX 400
for the money its worth it! my 400 has about every mod you can think of. before i could compete with the 450's! now i can blow them away! even some 500's!
December 27, 2009
OH
Excellent. must have
Very awesome upgrade. definitely a power notice
November 29, 2007
RI
great
its great
October 23, 2007
CA
Each question or answer submitted enters you into a:
$100 gift card monthly drawing and a
$500 gift card quarterly drawing!
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 2 questions Browse 2 questions and 2 answers
How you put the sleeve in in the head?
Christian G on May 30, 2017
BEST ANSWER: Had to take to machine shop to have it installed was around 200 dollars but that's they only way to have it done right because there's is a lot involved in installing it properly
How reliable is it?
A shopper on Nov 12, 2017
BEST ANSWER: Has worked out great much more power
RM Cash ProgramParts Finder