This look right to you all? I went by YouTube videos, and wasn't really sure...the manual makes it look completely different. It's on my 75 CB550. Wanna make sure it looks correct. The other thing is that the metal plates had a rounded side and a flat side but no instructions in manual or from the website. It's a Barnett clutch kit. I just put the flats facing outward. And no loctite on the threads? I didn't use any.
It looks better than those uber-thin plates that get sold to too many 500/550 owners, which slip after installation.
There are 2 thicknesses of cork clutch plates out there that will fit into this clutch. There are at least 3 thicknesses of plates being sold to owners of these clutches.
The OEM plates I have measured coming out of the CB550K bikes are 0.121" thick.
Some vendors are selling clutch plates from the CB750 that are the same outer diameter, but are 0.138" thick, like the Barnett plates.
So, if your clutch pack is OEM and you're changing plates, make sure the new stack height is similar to the original one.
There is some argument about the 1977-78 CB550 clutch plates, with some claiming that they are 0.107" thick with stronger springs, and others who said their OEM plates were 0.121" thick like in the 550K. The clutch lifter is the same through all the CB550 engines, so the lifter stroke didn't change.
Since around 2004 or so, Vesrah sells a (cheap) clutch kit that contains springs and cork plates that are 0.107" thick (which fits many post-1980 superbikes with 6+ plates in their clutches), and lately these kits come with stronger springs because the resulting clutch pack is so thin that the plates slip. It is my current belief that the bikes where the claim of OEM plates in those cases being 0.107" thick that are being changed [because they slip] for new plates of 0.107" thickness are repeating the same problem they are attempting to fix, from a previous wrench's mistake. I have not seen any OEM 550K/F that had 0.107" thick cork plates: they were all 0.121"-0.128" thick in all that I have serviced. But, since so many have been mixed up in this century, it might be tricky to try to fix the one you're working on!
Part of the difficulty now is in untangling the cork plates all the vendors have mixed into the 550's (and 500's) realm. The CB500K2 and the CB550K0 (USA) had cork plates which had rhombic-cut shapes to the corks, making them resemble a pinwheel, which was done to increase the slip-time of the clutch upon release of the lever. This was most noted by riders of the CB500K1 versus the CB500K2 bikes because dropping the clutch of the latter one for a dragrace start let everyone know the clutch was slipping for a while before it fully grabbed. The earliest 500 bikes I worked on had the square-cut corks on the plates, while my own 550K1 had the slant-cut version, as one example: the 500K2 bikes that came to my shop surprised me with the slant-cut version. Since the plates dimensionally are the same for either the slant-cut or square-cut corks' faces, the vendors worldwide have simply mixed them together everywhere, claiming them to be correct. If the thickness of the plates are correct, they will work fine when replacing the OEM parts: if they are too thin they will slip unless the spring tension is raised (making a tricky clutch engagement point in the 550) and if they are too thick (like 750 plates of 0.140" dimensions) they can break the pressure plate if one is not careful to tighten the bolts equally and slowly, or else use lighter springs because this thicker stack can make for a heavy lever pull at the handlebars. Some vendors have then stepped in with softer springs for those plates (Vesrah, for one). While all of these parts can be used successfully in these engines, one must know the type of plates being used and the advantage/disadvantage of each version. In my book I will note the OEM dimensions for the clutch plates and stacked heights, for reference. Outside those numbers, the builder is on his own.
Keep in mind, however, that I have not serviced nearly as many 550 bikes as I have 750 bikes: the ratio here is about 10:1 in favor of the 750 (which is in the hundreds, by my estimate). Outside of the clutch the 550 design is similar enough to the 350F/400F to be almost the same engine, just bigger (the 500F is different from these, mainly in the transmission area). In many ways the 500 bottom end resembled Honda's early DOHC 4-cylinder racing engines and the Hawk families of engines while the 550 transmission, in particular, led the way into Honda's future bottom ends.
