Addressing some things that were left unfinished since the last topic.
1) I'm sanding the gas tank down to bare metal and treating rust spots to prepare to repaint.
2) The brake caliper worked fine this summer, I got out to ride some but not a ton. I know I'll come back around on replacing the pads and seal eventually.
Now onto the new stuff. On the occasional ride I began to notice what I think is the clutch slipping. After the bike had been running a bit and I was making my way through a neighborhood with a lot of stop signs, I would shift up from first gear into second and hear a series of clacking noises. It felt like the shift wouldn't really take, for the first two seconds the power was feeling sluggish until something clunked into place and I really got going in second gear. Shifting up from there at higher speeds felt mostly fine.
So when I got my new garage space to work in, I decided the first thing to look into was the clutch. I have a copy of HondaMan's CB500/550 book and it's a terrific guide, I've studied what Mark wrote about the 550 clutch and used it to inform my own repairs. What I have done is this. I looked at my friction plates and with a digital caliper, determined that they were 2.8mm thick. I assumed this meant the plates were swapped out at some point, although strangely with new ones that were neither 2.71mm nor 3.2mm. Nonetheless, I have decided to try the remedy from the book of installing three CB750 friction plates at the front of the stack. Now I'd like to try and run this clutch to see if anything has changed.
But I have three questions to answer first.
Number One.
Are these the wrong springs? Assuming my clutch plates were replaced, it would seem likely that the springs were swapped too. And they certainly look to be bigger.
First, I'll mention about the clutch plates you have: the 2.8mm thick plates are the ones Vesrah (i.e., generic imported plates) is lately selling in place of Honda's 2.71mm thick versions. In that regard, they should work OK.
The 'clack' noise is not likely from the clutch, but may be coming from not-quite-engaged gear dogs and slots in the transmission. In this engine (and the 350F) this can happen during the 1-N-2 shift if the clutch didn't fully disengage and/or was 'dropped' too soon on top of the shift, before the gears had fully slid into position - this stops the sideways-slide of the gear(s) into their mates a little bit early, causing a less-than-full engagement. Oil drag, when the engine is cold, can increase this symptom, and it shows its head then if the more fully warmed-up engine shifts better.
More rarely (in this engine), if the dogs on the sliding gear are worn down, or its shift fork is bent a little bit, the gear with the dogs on it won't move far enough to fully engage the slotted gear (this can happen on any of the 3 such "pairs" of gears in this gearbox) with the result that it may rattle as those dogs are trying to find the slots until they do engage. That's what makes the noise.
In some cases, this just means the shift wasn't fully completed. This can come from several things, like:
1. the shifter arm being mislocated (on the wrong splines) as noted above, so your toe can't lift it far enough to firmly shift the gear during upshift, or
2. the little pins on the end of the gearshift drum are loose because the bolt/screw holding the top plate down isn't tight (this is more common on some of the CB750 engines, like the K5-6 versions with poorly-staked top plate screws on the shifter drums), or
3. a bent shifter fork inside the gearbox. (This isn't common on the Mid-Fours, though, but is quite common in the 750s) or lastly,
4. the gear dogs are worn and rounded, so they don't engage with a crisp edge into the mating slotted gear. (Again, this is more common in the CB750 than in these engines, but I have seen it in all of the SOHC4 before the CB650). This one happens in high-mileage (500/550) transmissions, like more than 25k miles.
When the engine is cold, the poor-dog-engagement situation may be different from when hot because the width of the 500/550 engine increases the slack between the gears on their shafts by about 0.5-0.7mm with temperature. Thus, the worn-dog-and-slot situation can get worse with heat, better when cold. This might help with diagnosing which 'bug' is annoying yours?
