Clicking Noise

Hi, I recently purchased a 1999 WR400F, and today, a clicking noise started coming from the engine. It sounds like it's coming from under the valve cover. However, I just changed the oil and filter, and had to loosen up the header to do so. When I started the bike and took it out for a spin to warm it up, it started making the clicking noise after 2-3 minutes or riding, and gets louder when the rpms increase. Other than that, the bike seems to be running just fine. Would the header be the primary suspect, or am I missing something?

Clicking would not likely be header. If it was misaligned it would most likely suck air and you would get a backfire on decel.


Take the valve cover off.


Pull decomp lever and get someone to kick it over so you can have a good look and listen without it starting up.

Did you put enough oil? More than likely worn top end

If the clicking is rythmic, it is in the valve train, and is most likely a broken shim bucket.

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