leaded gasoline in a YZ450F?

4 replies to this topic
  • CBreaken

Posted July 17, 2004 - 11:58 AM


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.

  • Wyatt

Posted July 17, 2004 - 02:07 PM


I ran leaded race fuel in my '01 which had a ton of hours on it with zero problems. I also run it in my '04. No prolblems.

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  • dvn

Posted July 17, 2004 - 02:41 PM


I've run a 50/50 mix of leaded race fuel and super unleaded in my 01' 426 from day one with no problems at all. I remember reading somewhere that the lead in the fuel helps to cushon (spelling?) the valve seats. Don't know if thats true or not but I haven't had to adjust my valves yet with over 80 hrs. on it.

  • CBreaken

Posted July 17, 2004 - 03:00 PM


Thanks for the replies guys. Actually the whole reason behind my running the 50/50 blend was because of the leaded fuels tendency cushion the valves at the seats. I know that I wouldn't gain any performace, just looking for long term reliability. It was my understanding that leaded fuels were only harmful to catalytic converters and O2 sensors. I wonder why yamaha added that disclaimer into the manaul :thumbsup:? I know leaded fuel leave behind more deposits. Could this be why it's considered harmful?

  • twistngrip

Posted July 17, 2004 - 06:53 PM


I think they say no lead for a reason. Why go with lead when it runs great on unleaded and it will obviously last a long time with unleaded. Just my .02.

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