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Engine noise 450


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Hey guys I am very new to this 4 stroke thing

I bought a 2007 yz450 used, it seems to me there is alot of engine noise, most notably a slight clicking sound. Not having a manual yet I am scared to even touch the engine other than oil changes, do you think the clicking is a serious problem or am I a uneducated 4-stroke rider?

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This is a 5 valve engine with two cams, these motors often make ticking noises at idle. If the noise gets worst or gets extremely loud when reeving the engine you may want to consider adjusting your valves. Make sure you have oil!

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  • 2 weeks later...

i have a 2003 yz450F and it makes a fair amount of engine rattle. I just bought it about two months ago. It starts well and runs like stink so I'm happy enough. Glad to hear the rattle seems to be part of normal YZ sounds.

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I have a small amount of noise on my 03 450, nothing like the ticking my 86 xt350 makes.

I do have one question, and sorry to high jack, but does anyone have any issues with the motor kinda missing at the top end when it is muggy out? It kinda seems to act like it is hitting a rev limiter, or missing, I also dont have the same power as when it doesnt do it. Mostly noticed in 1st gear.

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Anyone had issues with the Timing Chains on their 07's. I had two friends that their bikes jumped timing during our last xc race. One YZ450F and YZ250F. It did seem to me like his bike was making more noise than normal. I am used to RFS noise with KTM and Huskies but it seemed like his was a little louder from what I remembered earlier.

He had checked his valves just to make sure and they were in spec. On his bike nothing happened except jumping timing but the 250 bent a valve. Just a regular track but it did have mud.

Funny thing is that he put it back on time and it jumped again. He and mechanic are still looking into it.

Do the chains stretch on this model or is there an issue with the tensioner? His earlier YZ's were pretty much bullet proof. Just curious, if anyone has any info I would be glad to pass it on to him.

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Do the chains stretch on this model or is there an issue with the tensioner? His earlier YZ's were pretty much bullet proof. Just curious, if anyone has any info I would be glad to pass it on to him.
I've heard of only a couple of incidents like this. Usually, the cause in earlier YZF's is camshafts partially, or momentarily, seizing in the head. I'd pull the cams and have a look at the journals and saddles, and also check the clearance.

I'm not aware of any issues with stretching chains, or of a tensioner weakness. The tensioner was suspected as a cause of the valve failures in the '06 250F, but the speculators turned out to be wrong about that. YZF tensioners are one of those things that are so simple that they're brilliant. Basically too simple not to work.

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