The motorcycle of Theseus now has a new clutch assembly. This was very much a "while I'm in there" project but this one actually made sense. One of the assumptions I made when I bought this 48 year old motorcycle was that I would be best served by performing routine maintenance on all key systems. Working front-to-back, I made my way to the middle of the machine and it was time to perform one of the most invasive maintenance tasks required for the these motorcycles - a transmission input shaft spline lube. To perform a spline lube correctly, the transmission has to come out. On a shaft-drive motorcycle that means the back of the motorcycle also has to be removed so it requires a bit of work. There are videos scattered across the Internets showing folks performing this maintenance without fully removing the back half of the motorcycle but I tend to be a rule follower and "doing things the right way" is my maintenance battle cry. So, the back of the motorcycle was removed so I could do it right. And that's how I said another of my battle cries out loud - "while I'm in there..."
With the swingarm and final drive removed I pulled the transmission out to discover a mangled input shaft. Resolving this is an entirely separate story I'll tell later. Given the state of the transmission input shaft and the corresponding poor condition of the clutch mating surface I decided pretty quickly that a new clutch was required. A clutch kit from Bob's Motorcycles, a few extra bits to address a couple of other overdue maintenace items, and my trusty credit card, and I was in hurry-up-and-wait mode. Bob's staff is excellent, shipping was prompt, and several boxes of replacement parts manifested on my front porch. It then became time for wrenches to begin turning clockwise!
With the clutch removed I discovered that a couple of other routine maintenance items also required attention - the rear main seal and the oil pump cover o-ring. The amount of gunk in the bell housing indicated that both seals were beyond their usable life and required replacing. Neither of these replacements are difficult but one must have the parts on hand. I had a spare rear main seal on hand but unfortunately I did not have a replacement o-ring for the oil pump cover. So, a $4 part held up reassembly for an entire week. As you might imagine, I was a bit frustrated due to this inventory oversight. I called my friends at my local BMW dealer to see if they had the missing o-ring in stock but they didn't (which makes total sense - it doesn't make a ton of sense to dedicate inventory space to a part for a 50 year old motorcycle). They were, however, able to order it (and a couple of spares to keep on hand!). The o-rings arrived as pomptly as it would have taken to ship them from an online seller but ordering locally saved me on shipping. With everything finally in-hand, clutch kit assembly began.
Overall the process was straight-forward and completed in about 3 hours - including replacing the rear main seal and the oil pump cover o-ring. A few specialty tools are required, and I watched an instructional video a few times to make sure I got the assembly sequence right, but all-in-all things went well and a fresh clutch kit is installed.
