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Big Bore KitsBig Bore Kits

ATV Big Bore Kits

If you want to get more power out of your ATV, you can’t go wrong with a big bore kit. It’s a quick way to increase your engine displacement for more horsepower. For example, a Honda 400EX big bore kit will increase the engine displacement from 400 cc to 440 cc. This offers an immediate power gain.

We carry several brands that manufacture ATV big bore kits, including Wiseco and Cylinder Works. Both are respectable companies that make excellent products. For most machines, only one or the other is available (if any at all). How can you know what will work for your quad? The only way is to use the Parts Finder with your ATV’s make, model and year. Fortunately, big bore kits are available for many popular quads, including the Raptor 700, TRX450R, Z400 and many others.

If you’re looking for a little more power, a big bore kit is the way to go. And when you want to find a great price from a leading supplier, Rocky Mountain ATV/MC is your source. We have highly acclaimed customer service and policies in place to make sure your shopping experience is the best it can be. Pick up an ATV big bore kit today to find out for yourself!

Latest ATV Big Bore Kits Reviews – You could win up to $500 for reviewing products!

  • Cylinder Works Big Bore Cylinder Kit

    Cylinder Works Big Bore Cylinder Kit

    Fredrick in FL

    MXA and Rocky Mountain Both said install with no fu...

    But it really needed an ecu reflash on my 17 KTM 250sxf or it wouldn't really run. Sent to Tokyo Mods For reflash, That helped quite a bit, The terrible 17 KTM battery needed to be replaced for a bigger one. and the TPS had to be adjusted. Now with all that done and behind me, IT REALLY RIPS. im about 190lbs and it really helps my corner speed with that little extra oomph, i also went to 14/49 gearing and its pulling great.

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  • Yamaha GYTR Ported Cylinder Head Assembly

    Yamaha GYTR Ported Cylinder Head Assembly

    Eddie in FL

    Looks good but doesn't perform as good as it looks

    For the price it wasn't worth it it was too much bottom end torque you have to ride it very high in RPM

    Read All Reviews
  • KTM Big Bore Kit

    KTM Big Bore Kit

    Dana in MA

    Buy this if you can.

    Was bummed about the cost, but was happy when I got it. Was pleased to receive a KTM power parts head with insert which I was not expecting. Came with everything needed then some. Bike runs mint.

    Read All Reviews
  • Wiseco Big Bore 440 Kit

    Wiseco Big Bore 440 Kit

    brandon in OH

    Great big bore kit for the ltz 400

    Very great product huge power gain

    Read All Reviews
  • Dubach Racing Engine Relocation Kit

    Dubach Racing Engine Relocation Kit

    cody in MO


    Put this on my bike along with the Dr. D radiator lowering kit and the two together made my bike handling a lot better than it ever did before. Recommend both kits for anyone with a 10-13 yz450

    Read All Reviews
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