Tell you what, when I bought my CB350 twin tensioner setup, I was unpleasantly surprised that the roller alone costed about 40 euro!!!! Well, I've said here many times that I pay willingly to a company that still sells me spares after 35 years. But furthermore, I presume the material of the rubber is not simple rubber.
True, you have to pay 50 cents or even 2 bucks for a bolt alone, but have you seen how specials those bolts are? You get the list of measures to the hardware shop and when they see "M6 x 32", "M5 x 43", they just tell you: "sorry, I only have them in 5 mm increments". So you have to buy the next longer and cut it yourself, or put the shorter one and discard those two additional mm of bolt thread. But you get your part number with you and you get the right bolt at the right measure, not to mention the "pan", the part at the bolt head that is not threaded so not to ruin the cases. If you are lucky you can buy a longer one that has the same pan lenght, and cut it at your desired lenght, but the time and cost exceeds the cost of the Honda part. I've been charged more to chrome some bolts than the price of a new bolt!!!! and the same goes to the blinkers!!!!
I replaced the case bolts but only to have allen heads. ¿The rest? Honda OEM except some zinc plated washers that you can get by the bulk, or the split pins. Even the nuts are different. They have the same thread, but not the same size. So you can tear down the whole bike with a 10, 12, 14 and 17 wrench. That is not standard for M6 or M8.
Seriously, if you tear down a whole Honda bike and you rebuilt it, you can't help but notice how well thought every single aspect of those bikes were. Some of them were flawed or suffered from early teething, but they were very quick to react. As an example, the chain problem in the early 750's was sorted out less than one year after the bike went into production.
Raul