Im a newby to this site. I was wondering if you guys can help me. I seem to have a random rattle from around the cylinder head area of my 06 WR450F.It only happens on part throttle load. It`s quiet(ish) on tickover and the noise dissapears if I nail it hard. I have only just bought this bike 2nd hand. Its always done this. The bike starts really easy and goes like stink when nailed. So far i`ve pulled the left side generator cover off. All seams well. And i`ve also removed the cam chain tensioner and checked that it winds back by itself under spring tension...all is well. I`ve pulled the cam cover off and checked the cam chain. It looks tight - even when kicked over slowly. So i`m stuck. Is it possible that the tensioner can wind back under certain conditions. Also is it common for the camchain to wear on this bike? And lastly can anyone recomend an online supplier of camchains/tensioners here in the UK. Sorry for the long post.