Can I run pump gas in a 13.5:1 yz450?

3 replies to this topic
  • atropine

Posted October 15, 2008 - 09:43 AM


My 06 YZ450F is due for a piston change (probably has at least 100 hours on the motor, but is running fine), so I thought I would put in a high-comp piston. I want to get a CP, and they make a 13:1 and a 13.5:1. I don't mind running high-octane fuel, but there are times where it is very inconvenient to get it (the closet 100-octane pump is about 60 miles away). I searched this forum and it seems there is a variety of opinions on whether 91-octane will work OK with a 13.5:1 piston. What is the real story?

  • grayracer513

Posted October 15, 2008 - 09:50 AM



(advanced search string: pump gas AND piston, no poster name)

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  • dirt_rider93561

Posted October 15, 2008 - 09:58 AM


In my RMZ I am running a CP 13.5:1 piston and I run it on pump gas. When I get ready to rebuild mine I am going to step down to a 13:1 piston, just for the piece of mind. You can run the 13.5:1 piston on pump gas, but I would recommend you using like an octane booster to bump up the octane on the gas.

  • atropine

Posted October 15, 2008 - 10:52 AM


Thanks guys; exactly what I needed to know. Gray, I had seen one of those posts, but the other 2 you linked seemed more helpful and answered my question well. Thanks again.

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