I use a NC31 which belongs to a friend but I take care of it while he is away. However it is very noisey with a rattling sound from the engine as it idles. Someone said its the cam chain tensioner. How can I tighten this without having to disassemble the engine or going to a shop. I am in Thailand and as a foreigner that can be expensive and language issues as well. The bike works fine otherwise. Any advice is welcomed. Also can someone give me a link to a free download of a worksop manual. The bike is a 1992 CB400 Super Four

Thanks