Is this normal?

Before I ask this question, please forgive me of my ignorance of 4 strokes, as I raced 2 strokes my entire life until I made the switch to a 2004 YZ 450 back in November and am pretty much clueless.

Here is what is concerning me. I fired-up my bike tonight before I changed the oil and filter like I do after every ride, and I don't know why I did it, but I stuck my head down next to the outside of the cylinder to listen. Every time I revved the bike a little I noticed somewhat of a clattering/knocking sound that got progressively louder the higher I got into the rpm's. Is this normal for 4 strokes? Do I need to post a vid of it? Any advice would be greatly appreciated.

I have an 04 also from 98 to 09 yz4xxf's are a pretty noisy motor maybe you just never noticed it before?? I am sure Gray will have an answer for you.

I am a 450 rookie too but I would guess the noise has something to do with your timing chain, tensionor and or guides. But I am not a 4 stroker pro just yet.

When ever you work on your bike, it always improves your hearing. :thumbsup:

Unless you are familiar with it, you should compare yours to another one before you worry too much about it. Also, if you have a skid plate, that can exaggerate the noise level, and if you R&R'd it for the oil change, it can sound entirely different than it did before you took the plate off.

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