valve adjustment

How often should the valves be adjusted on a yz 450? :thumbsup:

When they are out of adjustment. Kidding aside, you should check them maybe 10-20 hours after break-in and then about every 30-40 hours or so. Mine haven't gone anywhere in the 65 hours I've put on mine.

Mine have gone about the same. And in addition they are super easy to check if you have the gauges just go by the book. I have a friend who rides enduros, motocross everything, but he rides six days out of the week. Just a guess but he probably has 200 hours on his and valves are still in spec from the factory. He uses lead additive, it is suppose to cusion the valves seats and reduce wear.

I am curious what it sounds like when your valves need adjusting because my 426 started making a funky noise lately... its a stokely sound, like changgg, changgg, changg.. and now it back-fires when I let off quickly from WFO.. Any idea ?

- Jason

Most often the valve clearances get tighter, so there is no noise to be heard. If you've noticed a new noise it's most likely not due to excess valve clearance.

I am curious what it sounds like when your valves need adjusting because my 426 started making a funky noise lately... its a stokely sound, like changgg, changgg, changg.. and now it back-fires when I let off quickly from WFO..

Back-fires "bang" or pops "popopop"? Anyways, sounds more like you're running lean. If the temps you ride in haven't dropped lately, I would check for air leaks.

I checked mine after about the first 25 hours and one intake valve was too tight and had to be reshimmed. I just checked them again after 9 months of riding and they are all in exactly the same place they were after I replaced the shim.

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