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vic2340

2009 Yz450f top end rebuild, thinking about a 13:1 piston

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Hey everybody, I have a 2009 yz450f and the bike has quite a few hours on it so I think its time to do the top end before something bad happens. I was looking up pistons and I realized that a 13:1 compression ratio piston for my bike only costs about 30 bucks more. Stock compression ratio is 12.5:1, so seems worth it to me, however I have a few concerns. Will adding this piston create more strain on my engine? Will I have to run a higher octane oxygenated race fuel? Will this create any issues with my jetting if race fuel doesnt have to be used? And finally will I need to service this top end more often making it more expensive than that 30 bucks more in the long run?

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Curious to hear any replies myself. I just did a top end about 6 hours ago (riding time) and I went back stock because I got a crazy good deal on stock top end components. But I was leaning toward a higher compression piston myself and had similar concerns.

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Yeah it seems like nobody knows or cares about this topic. I think im just going to get a stock compression piston however, its not like I really need the extra power. A 450f stock should be enough power for anyones needs.

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wow that has to be the best deal ive ever seen. Thank you so much for that link. I just have to know arent there more gaskets i will need then just the head and base gasket? I dont know for sure but I could have sworn their were more than that. Those by the way are the only gaskets given in that kit.

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That kit is the same one I just purchased. I have 4 hours on my new top end. The kit includes everything you need, however I would replace the timing chain as well if I were you. They tend to stretch after a while.

Edited by Yamaryder29

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