Hi, i too have cx 650 c (30,000 miles) well pleased with it untill i had to have engine rebuilt(£1000) using gen. honda parts and gaskets ; a big end lining collet had slipped causing damage, that had to be "white metalled"(made good).the guy who fixed it showed me the timing chain (it was well loose and was able to flex unaturally like a horse shoe) and tensioner ...he said it was original from new, these two items were both replaced as well(he said the tensioners were modified to a thicker design later on as the early models were too thin and were prone to snapping after about 2000 miles. so if you havent checked it then it might be worthwile doing so.hope this is of use to anyone....i now have my bike back, the engine is practically run in and runs well sweet with a nice tight engine...still a fine machine though..