No two-stroke engine needs lead as there are no valves. There are some big two stroke engines with valves but they are usually Diesel engines and the valve seats are hardened. Those Engines are not used in Motorbikes. Some off them have 4000 HP per Zylinder and they are used in ships. There are some smaller ones in Traktors, Trucks, Generators ... Anyway their diesel fuel is not leaded too.