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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

    MARTIN in CA

    The vertex piston oil ring was pretty cheesy

    Not to sure how long this thing will last . Over all every thing was allright but the oil ring was pretty cheap . You would think they would give a better oil ring thats the only thing i could see going wrong .the stock pistons oil ring was 3 times stronger. Will let u know how it holds up thanks

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  • Yamaha GYTR Ported Cylinder Head Assembly

    Yamaha GYTR Ported Cylinder Head Assembly

    James in TX

    GYTR Head

    Expensive engine mod but if you are serious about powering up your YZ grab this and get to the front. Need to use VP u4.4 but you should already be using that if your racing at all . Be sure to set the new mapping to the ECU !

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  • 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

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  • Wiseco Big Bore 440 Kit

    Wiseco Big Bore 440 Kit

    TROY in CA

    Best mod ever

    This was buy far the best upgrade I did to this quad. Great fit.

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  • Athena Big Bore Kit

    Athena Big Bore Kit

    DAVID in CA

    Athena 290 big bore wr/yz

    I have ran this big bore for three years and have great success with it, makes great bottom end and mid range power. I have ran it on my 08 yz250f with a wr trans and rekluse clutch and hot cams, awesome woods bike.

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