2009 yz450 shock pressure

7 replies to this topic
  • Yzflier977

Posted January 31, 2013 - 02:16 PM


Getting ready to change my shock oil on my 2009 yz450. I previously had a yz250 and had installed race tech gold valves front and back and changed my own fluids. I had race tech's chart for shock pressure so I knew where to set it for that bike, but on the 450 I'm a little lost. Owners manual doesn't specify a psi. I'm guessing around 140-150 psi? And yes I have an air compressor that goes that high. Any info is appreciated.

  • Yamaryder29

Posted February 01, 2013 - 05:34 AM


I've had some suspension shops tell me 150, others say 170. It's rider preference. Pro Action told me 130-190 psi, so 140-150 is fine, however, you don't fill it with air. The shock gets filled with nitrogen using a no-loss chuck to accurately fill the bladder.

  • grayracer513

Posted February 01, 2013 - 08:07 AM


Most people are good with 145-160 in the shock.

Don't use air. You can, and you'll always find people who say it's perfectly fine, but there's a reason manufacturers spend money on nitrogen instead of just compressed air. Shocks run hot. Really hot. Ride yours hard for an hour and see what I mean. Nitrogen changes pressure less with temperature then air does, so the shock's performance changes less as the heat changes. Bottled N is also dry, compressed air contains water.

  • Yzflier977

Posted February 01, 2013 - 02:19 PM


Thanks guys, I'll end up using air as I have for the past 12 years when rebuilding my shock on another bike. I understand the pros and cons for each, but for how I ride it's fine. Besides my local shop charges $25 just to hit it with nitrogen for 5 seconds. Believe me when I say I don't ride my bike hard enough for the differences to matter with heat and pressure changes. I just didn't know what the psi setting was for this particular bike.

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  • etuke

Posted February 01, 2013 - 03:18 PM


all i used in the kawi was air for last 2 years and worked fine for me too but like you i'm not that agressive.

  • FZ1426

Posted February 03, 2013 - 06:30 AM


Even if you don't ride hard nitrogen is prefered as the oxygen (and other gases) in air will deteriorate the rubber bladder over time. Nitrogen will not.

  • Yzflier977

Posted February 03, 2013 - 08:10 AM


I rode my yz250 for 12 years using just air. Hard to argue with my own experience regardless what others say. Bladder in that bike held up just fine and shock performance never suffered for my riding level. Funny thing about thumper talk is it tags me as a "newbie" based on the number of posts. But that in no way belies my knowledge or experience.

  • etuke

Posted February 03, 2013 - 08:31 AM


they charge $50 to recharge shocks here so if the bladder lasts over 12 years on free air then I'll risk it too,plus the bladder only cost $10-$15 and 1 litre of oil.If your a pro rider or just want it done then by all means spend the cash,to each their own.

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