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

5 replies to this topic
  • vic2340

Posted May 02, 2013 - 07:56 PM


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?

  • Yzflier977

Posted May 05, 2013 - 03:31 PM


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.

  • vic2340

Posted May 05, 2013 - 08:20 PM


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.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Yzflier977

Posted May 06, 2013 - 06:56 PM


Yeah this is what I ran into when I posted something similar a few months back. If you're going to go back stock try this link.

  • vic2340

Posted May 07, 2013 - 05:49 PM


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.

  • Yamaryder29

Posted May 07, 2013 - 05:56 PM


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, May 07, 2013 - 05:57 PM.

Related Content


Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.