Time between valve adjustments 09 yz450


4 replies to this topic
  • yz250_TX

Posted November 14, 2015 - 05:50 PM

#1

I've got an 09 yz450 that I bought with 116hrs on it. I'm currently at 131.

 

According to the maintenance log I got from the previous owner, the bike got a top end, timing chain, valve adjustment at 46.6hrs, and another valve adjustment at 91.2hrs. It doesn't say what the clearances were or what they were adjusted to. 

 

I just checked the clearance the other day, and I was still within spec. 0.21mm on exhaust, 0.11mm on intake. I did not make any adjustments, a new shim would be 0.05mm and would put me slightly out of spec on the high side. 

 

So I'm 40hrs since the last adjustment, and previously he went 45 between adjustments. 

 

I figured I would give it another 5-10hrs, and check again and adjust as needed. Unless there's any reason I should just adjust now? 

 

Also, is it time to start worrying about another top end soon?



  • Dklassen

Posted November 14, 2015 - 06:46 PM

#2

My buddies 09 YZ450 has an estimated 200 hrs and that's a very low estimate. The valves on his bike were never adjusted. He had the valve clearances checked in 2014 and they were within spec and didn't require adjusting. His theory is to keep running it until it has a problem.
I have a 2009 CRF450R with an hour meter. My valves were within spec at 135 hours and never adjusted from new. I replaced the valves/springs/etc at that time because I wanted to ensure I didn't have a problem. When I inspected my old valves the didn't look very worn compared to others I have seen but I know that the parts were fatigued from use. Now my bike has 160 hours on it without an issue.
Both our bikes run strong. You have to decide how long you can run the valves for. A modern 450 rarely gets revved for all its worth so a head can go a long time however if something lets go it can get expensive and dangerous. If I were you I'd have the valves & springs replaced sooner than later as the hours are adding up and it's heading into it's 7th season of use. I sent my head away intact with new OEM parts and had the seats ground and the head re-assembled and "bench set". When it came back I just bolted it on and it started right up.

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  • UncleLuke

Posted November 19, 2015 - 07:40 AM

#3

I've got an 09 yz450 that I bought with 116hrs on it. I'm currently at 131.

 

According to the maintenance log I got from the previous owner, the bike got a top end, timing chain, valve adjustment at 46.6hrs, and another valve adjustment at 91.2hrs. It doesn't say what the clearances were or what they were adjusted to. 

 

I just checked the clearance the other day, and I was still within spec. 0.21mm on exhaust, 0.11mm on intake. I did not make any adjustments, a new shim would be 0.05mm and would put me slightly out of spec on the high side. 

 

So I'm 40hrs since the last adjustment, and previously he went 45 between adjustments. 

 

I figured I would give it another 5-10hrs, and check again and adjust as needed. Unless there's any reason I should just adjust now? 

 

Also, is it time to start worrying about another top end soon?

 

Depends on if any of the valves "move". I like to keep a log on new bikes and check every 15 hours for movement. Yamahas are usually solid for a long time unless the thin Ti hard coating wears off, then the valves go fast!



  • Krannie McKranface

Posted November 19, 2015 - 03:59 PM

#4

As soon as it gets harder to start hot



  • Wiz636

Posted November 19, 2015 - 08:11 PM

#5

My '08 had 400+ hours (metered) on it when I sold it and I never had to adjust the valves. I checked them every 50 hours or so and they never went out of spec.

 

I put in a new piston and rings at about 220 hours. Always started and ran great.

 

The key to valve life is to always keep a clean, well oiled air filter on the bike.







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