I was just looking through the owners manual for my 04 YZ450F and noticed under the "FUEL" section it says not to run any leaded gasoline because "use of leaded gasoline will cause severe damage to the engine internal parts such as valves, piston rings, and exhaust system, etc." Is this true, or is it just some enviornmental scare tactic forced upon Yamaha? I've been running 50/50 76 premium pump gas/VP red for the last 6 months with no porblems, but then again I haven't tore down and inspected the engine either. Any thoughts and or experiences would be appreciated. Thanks.