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Big Bore KitsBig Bore Kits

Dirt Bike Big Bore Kits

Every rider craves more power from their dirt bike, more torque to pull from. Modifying your top end with an aftermarket big bore kit can be a fairly easy way to deliver the power that you’re after by increasing torque and horsepower to give you noticeable power gains through all ranges.

Aftermarket big bore kits include larger pistons and cylinders which typically increase the engine size by around 3 mm – and it only makes sense that the larger the engine, the more power you’ll get. The cylinders look nearly identical to stock and usually include everything you’ll need, such as:

  • Piston
  • Cylinder
  • Piston rings
  • Wristpin
  • Circlips
  • Top end gaskets

These kits are made for easy installation and include all the parts you will need to completely rebuild your top end. If you’re up to the task of doing the mechanics, we’ve got a part one and part two instructional video series to show you how to replace the top end on your dirt bike. Make sure you have all the tools you’ll need as well as a service manual and we’ll do our best to guide you through the installation.

Leave your competition in the dust or just impress your buddies with your new-found power and performance when you upgrade your top end with a big bore cylinder kit by Cylinder Works from Rocky Mountain ATV/MC today!

Latest Dirt Bike 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.

    Read All Reviews
  • 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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