I have a 09 250xc-f with 70hrs on it. The engine is fairly quiet (for a 4t) after start-up but after about a half hour of riding it makes a ticking sound that is louder than after start-up. I bought the bike at 60 hrs. I put a new top end in it when I got it and a dirt tricks tensioner. It had the same ticking sound before the new top end and tensioner. Valves are in spec. and the bike runs great. Very minimal wear on the stock piston. I was just wondering if the louder ticking after it gets hot is normal or if anyone else has this issue?