Please select make, model and yearBig 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!
Daniel in NJ
Bought this kit, install went great! Installed this and hotcams at same time. Broke in cams and cylinder as per specs. Took out for first ride and changed oil after, FOUND BROKEN WRISTPIN CIRCLIP IN OIL. Called company, they overnighted part without hesitation. Found other half in engine, removed it with magnet. Installed new ones, bike ran like a dream. 2 months in, let clutch out of a turn and the bike died on the spot with a small pop noise. Broke down engine AGAIN and found the wristpin slide out of place due to another failed circlip, the connecting rod threw the piston up into the head bending my valves and bent the connecting rod while scoring my cylinder wall at the same time. 2,000 in damage thank youRead All Reviews