We are offering motorcycle engine valves. Renown engine valves are located in the cylinder head. The main function of the engine valves is to let air in and out of the cylinders. That air is used to help ignite the fuel which will drive the pistons up and down. the inlet valves of course let air in, and the exhaust valves let exhaust air out. The more air you can move air in and out of the engine the more efficient, and therefor power the engine will have. This is why the engine valve plays a pretty critical role in an engines performance.