[Andy04180]

One of my co-workers asked the question, Why are bikes compression ratio so high without any detonation running 91 octane gas? ( he's a gear head but never messed with bikes ) I know the GSXR's rage about 12.3-12.8:1 compression. Also, does anyone know what the Engine blocks are generally made of to withstand this pressure. Figured this would be the place to pick someone's brain. Thanks for the info, will relay on when responses flow in.