Wiseco (K1229 77.0mm 10.25:1 Compression Ratio 4-Stroke Motorcycle Top End Piston Kit Fits: Suzuki GS1150 1983-86 Dedicated forgings are used for superior strength to weight ratio utilizing aerospace alloy with a dome designed for improved flame travel and detailed skirt shape and profiles for stability and smooth operation in the cylinder bore Compared to cast pistons, forgings are tougher and more durable, and will stand up to the abuse that high performance motorsport applications require Each Wiseco piston is designed with the proper installed clearance to produce the most power, least wear, and best seal at running temperature, for each application 77.0mm bore; 10.25:1 compression ratio; total displacement 1229cc; includes head and base gasket; notes - 20mm pin