i honestly said the same thing that my header shouldnt be loose but mine has been comin loose about every week so i hear the noise all the time haha im about ready to get some loctite and fix it all but ya its worth a shot.

 

Did your header make a ratteling noise or a ticking noise? I think it might be a possibility that its loose because it sounds like there might be an exhaust leak towards the front of the bike. I havent found the time to look at it yet but it will be the first thing I troubleshoot

 

What kind of oil are you running?

I had a very similar sound coming out of my bike - sounded like valves tapping (likely was!) - I was running 5w50 100% synthetic motorcycle oil. I'm guessing that it was a little too runny when cold and thus the noise. I switched back to Honda GN4 and the noise is GONE!

If you're due for an oil change anyways, it's something to try...

 

I run the Honda GN4 as well, I figured out where the noise was coming from, I was due for a new chain. I took the front sprocket cover off to see if there was a rock or pebble stuck inside of it, when I removed it I looked at the metal spacer between the cover and the block, the chain was rubbing on it.

Anyway, I bought a new chain and all is well now. The bitchsounds like she's brand new again.

Thanks for all the suggestions