Big-bore Yamaha XS650
Yamaha XS650 fans looking for more grunt out of their old twin should check out the big-bore cylinder and piston kit from Mikes XS. The cylinder casting features substantially larger cooling fins that extend out as far as the cylinder head fins for enhanced cooling, while the forged pistons feature MoS2-treated skirts, an oil channel for enhanced piston pin cooling and valve pockets for large valves. The lightweight 9:1 pistons weigh approximately 455 grams, or around 1 pound each. Fits 1974-1984 XS650 engines. $719.92. MC
