Hi all, We just bought a C90 08. I have 250 miles on it I noticed a not sure if it is a knock or valve noise while engine is under load such as rev up in each gear. If I put the bike in neutral and rev it up I can here what sounds like the valves. Never having a C90 before I am not sure if this is normal or if there is something wrong with the engine. Hope someone can help with this.