Big bore kit for 2002-2018 Yamaha YZ85. This cylinder kit from Athena increases the bore diameter to 53mm which is roughly 105cc of displacement.
This cylinder features a nickel-carbide coating on the aluminum cylinder to increase durability. The forged piston comes molybdenum coated for longer wear life.
The water jacket of the cylinder is improved from the stock design for increased flow rate.
This does not require the use of a stroker crank like the 112cc kit. This is designed to bolt up to the factory engine. In some cases, a small amount of material may need to be removed from your factory engine.
Comes with cylinder, piston, wrist pin/clips, head, new hardware, needle bearing, and gasket kit.
*This is a high-performance race item. We do not accept returns on used racing parts.
**This can not be used to replace the cylinder on the 112cc stroker kit. The cylinders provided with the stroker kits have been machined differently to accommodate the crankshaft. If you need a replacement cylinder for you stroker kit, feel free to email us and we can special order it.
Athena part number: P400485100038