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Wiseco Big Bore 440 Kit
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Wiseco Big Bore 440 Kit

Our price: $331.80$345.95

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Additional Videos

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  • 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

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0 of 0 people found this review helpful.

Best mod ever

Comments On Jan 13, 2015:This was buy far the best upgrade I did to this quad. Great fit.

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1 of 1 people found this review helpful.

RMATV customer service and product performance

Comments On Jun 26, 2011: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.

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1 of 1 people found this review helpful.

I would definitely recommend it

Comments On Jul 29, 2010: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.

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1 of 1 people found this review helpful.

KFX 400

Comments On Dec 27, 2009: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!

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6 of 11 people found this review helpful.

Excellent. must have

Comments On Nov 29, 2007:Very awesome upgrade. definitely a power notice

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6 of 14 people found this review helpful.


Comments On Oct 22, 2007:its great

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