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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!

  • 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.

    Read All Reviews
  • Cylinder Works Big Bore Cylinder Kit

    Cylinder Works Big Bore Cylinder Kit

    David in Texas

    365cc for KTM 350sxf...buyer beware

    Cylinder kit goes together nicely, but Cylinder Works gave no support after the installation of this kit. The kit obviously changes the fuel needed, which will require a ECU software change, they offer zero support except a jpeg of suggested settings.

    Read All Reviews
  • Dubach Racing Engine Relocation Kit

    Dubach Racing Engine Relocation Kit

    KEVIN in UT

    Easy Install

    Smooth instal.Take your time and follow the instructions.Made minor improvemen to the bike handling

    Read All Reviews
  • 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.

    Read All Reviews
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