2011 yz450f valve question?

3 replies to this topic
  • Blaz1

Posted April 09, 2014 - 09:35 AM


okay so i've had the bike for about a month, the guy before me said he took the bike to his mechanic and had the valves looked at to see if they needed adjusted. The mechanic supposedly said that one of them was a little bit tight so he shimmed it accordingly.


So i was riding this weekend in some real tight wooded areas and the bike ended up overheating out the overflow so i shut it down to give it a break and cool off. when i was looking the bike over i noticed the hose to connect the two radiators together was not attatched to the left one!!


I was definitely surprised that it had not overheated before...


I took the airbox off yesterday to get to the hose and i thought while i was already in there i should check the valves...


I have all the marks correct, both cam gear dots are parallel with the head and the flywheel mark is aligned with the mark on the stator cover.


Spec for the intakes is like .003in-.0059in


i couldnt even get a .002 in either of the intakes. Now in the past when i've had valve problems with a 250f it wouldnt start at all if the valves were tight. But this bike starts 2nd or 3rd kick cold everytime? is that because it is fuel injected?


i was also thinking that i could be on the wrong stroke? and the cams aren't in the right area's? 


If they are that tight then im most likely looking at new valves and seats cut...



  • grayracer513

Posted April 09, 2014 - 11:56 AM


If you are on the wrong stroke, the cam lobes would be down against the lifters and there would be no clearance.

How much real run time since the valve adjust?

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  • Blaz1

Posted April 09, 2014 - 02:43 PM


Ive ridden the bike at least 10 times since ive gotten it. Probably put 15 hours on it. 1 hare scramble on it also for a hour 45

  • grayracer513

Posted April 10, 2014 - 06:29 AM


Then, I would say, shim it to the correct specs and ride it for 3-5 hours and recheck.  If they've tightened again, it means the valves are worn out.

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