Attributes . Forged from high-silicon aluminum alloy for maximum strength and dependability.. Innovative forging design and piston skirt provide maximum horsepower and torque.. Wiseco High-Performance piston kits are priced with piston, rings, pins and circlips (unless noted otherwise).. Oversize pistons require cylinder sleeving.. SPECIFICATIONS. Displacement: 249cc. Bore - Standard: 66.4mm. Bore - Actual: 66.40mm. Bore - Oversize: STD. Stroke: 72.00mm. Cylinders: 1. Note: Pro-Lite. Note: Nikasil Bore. Note: Racers Choice. Note . Values