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czechalien

2006 yz450f top end and valve question

4 posts in this topic

2006 yz450f well taken care of, but now I have about 55 - 65 hrs on it after top end done by Mark Klein aka MxTuner.

Now I'm being told top end is needed along with valves which I just measured at intake: .004 .005 <.004 exhaust both .008 had that adjusted yesterday because I had some starting issues (fixed now).

I'm being told valves need to be replaces every 100 hrs and top end every 40 hrs.

Could you, please, advise me as to what I should do

Thank you very much.

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How many hours do you have on the bike and have you done any other motor work to it? How many times have the valves been shimmed? I have an 06YZ450 with 240hrs on the original parts and Im just now doing a rebuild as a piece of mind. I only had to adjust my valves after break in and they have not moved since. I personally think the 40hr thing is a croc. I would keep doing the proper maintenance on the bike and keep an eye on those valves for movement. If they move again soon then yes they will need replacement. You could have the same bike go 240hrs on an original motor and another bike of the same year need work at 40hrs or just blow up. You never know. Hope this helps.

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I had the top end done about 55hrs, never bottom and i know the previous owner and he never done it either or valves.

I was told, that the piston after about 40 hrs starts to wobble little and that damages the cylinder, therefor I should replace the piston, pin, cam chain, piston rings, head bolts and now since the motor has around 100 hrs i should replace the valves, buckets and springs.

Total about a $1000 or so :ride:

Though the bike runs great I have no issues as of now

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I have owned a few 450's and none of them were rebuilt until I had atleast 200hrs on them. I installed hour meters so I know the engine time was acurate. If you have the money then I would say why not, but again, I would keep an eye on the valves and ride it.

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