Sorry if this has already been covered but...

There is a loud ticking/knocking sound everytime I ride. I assume its the valve timing. It is consistant everytime I hope on the bike, and the rythem is always constant. It gets super loud as the bike temperature increases. Drowns out my exhaust and other bike exhausts around. Is this normal for our bikes? Is this something to worry about?

btw its on a 2008 America - Carb version, everything stock, removed 1 baffle in each exhaust.

Thanks