My GTR1400 started rattling on start up after about 3000kms,timing chain tensioner. Ran Motul 7100 10w60,guess what , no rattle on start up any more, even after bike is left for a month or more and all the oils drained back to the sump. I now run Amsoil 10w 40,still no rattle on start up after 10,000kms.
Suspected reason, the thicker oil pushed the tensioner to the next ratchet tooth on the tensioner, apparently the ratchet teeth are very fine, hence the timing chain tensioner is now placed firmer against the timing chain, no rattle on start up.
Try it.