First, sorry about language, i`m not speaking english natively. I have just bought -03 wr 450 and wondering about abnormal noise from engine. I`s like rattling sound of something being loose, i can`t locate source of the noise exactly but it ain`t clutct or gearbox, thats for sure. Noise is irregular and it`s stroger when engine is cold. On low rpm noise is clearly present, on higher rpm noise vanishes. What could cause that kind of noise? Automatic decompression system? Slack timing chain? Something else? Any ideas?