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NorCal426JAY

Yz426 motor noise?

6 posts in this topic

Hello, I have a couple questions I was hoping someone could help me with. My 2001 yz 426 started making a pretty good clacking noise the other day. It stays consistent at all rpms. No valve problems, runs very well. Just got loud all of a sudden. Took it apart and was wondering how noticeable rod play would be.

Any other ideas would be appreciated

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It depends on how much rod play there is, of course. The clearance is measured by rocking the rod side to side on the bearing (NOT sliding it back and forth) and measuring how much the top of the rod moves. The max is 2.0 mm.

You should also check the crankshaft drive gear nut.

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Hi, thanks for the response. I have checked the crank gear nut. I took off the clutch side cover and checked everything in there. All was nice and tight.

I am going to get a dial indicator and check the rod play. My valves were off a little, do you think that would sound similar to a clacking sound?

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If they were loose, yes, but that would be unusual. Check the condition of all three cam chain guides and the cam saddles for scoring.

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Stoked! It turned out to just be loose valves. Put it back together, and the noise is gone. Back to normal. Thanks for the help grayracer.

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how loud was it, mine is also making a noise, not sharp, just there, sounds like a DR350 any advice

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