any experience w/cylinder works big bore kit?

3 replies to this topic
  • vet45

Posted June 16, 2011 - 05:40 PM


does anyone have any experience with a big bore kit and or with the stroker crank also? quality? fit? performance? considering one for an 09 yz450f.

  • OUCR250R

Posted June 17, 2011 - 05:38 AM


Do it! I put one on my bike about 10 hours ago and it has made the machine a completely different bike. It has so much power off the low end it is unreal. The pistons and cylinders are matched to within.0004 or something like that and I can attest that the engine noise is down significantly from the OEM setup. I only have 10 hours on mine riht now, but so far so good!

Edit: My sig is old, I have a 2009 YZ450F also

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  • Michigantrailrider

Posted June 25, 2011 - 06:45 PM


Just put a big bore on my 03. No problems with fit issues and it made my bike stronger on the bottom end. On tight single tracks, my bike is easier to ride now. Overall, I am very pleased with the kit.

  • big bore morgan

Posted September 07, 2011 - 09:28 PM


im riding a 2007 450 at 3700ft..what r u guys jetted at?

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