Cylinder Works 02-18 Yamaha YZ 85 85cc +5mm Big Bore Cylinder Kit 103.5cc 8.2:1 Comp. 52.5mm

This is the Cylinder Works Big Bore Cylinder Kit for your 2002-2018 Yamaha YZ 85. It takes your 85cc engine and bumps it up to 103.5cc, giving you a significant increase in both displacement and horsepower. If you're looking to get more out of your YZ 85's engine, this kit is designed to do just that.

The kit itself is built around a high-quality 2618 aluminum alloy cylinder, which is known for its strength and durability. This material choice is important because it can handle the increased stresses that come with a bigger bore and more power. Inside, you'll find a hand-matched Vertex piston, specifically chosen to work with this larger cylinder. To make installation straightforward, it also includes a complete top-end gasket kit with all the necessary O-rings. Buying it as a kit saves you the hassle of sourcing individual OEM parts, and it's often more cost-effective.

This kit is designed to look similar to the stock cylinder externally, but its internal design is performance-driven. With a compression ratio of 8.2:1 and a bore size of 52.5mm, it's a well-built package for riders wanting improved performance from their Yamaha YZ 85.