my bike has a ticking rattling sound in the morning when cold thats bad at low rpm, when it revs above 2k it goes away, same when its warm. I think it could be the chain? but up for any ideas. if it is the chain would a thicker oil help, say from a 10w to a 15w , do they snap when old or will it rattle for years and keep going? got a quote for $400 to replace chain is that too much or ok?