Please select make, model and yearBig 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:
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!
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