I’ve been working on restoring brake disks and have found some codes stamped on them. They don’t appear to be date codes to me. Anyone have a clue what they mean? Right now I have a NOS K1 disk holding a place on #97 until I get a disk refurbished. I should have kept track, and maybe it doesn’t matter, but any opinions which one may have come off #97?

Some of the numbers are hard to read and don’t turn out well in the photo but here’s what I think they are.

W27S


A-17


A206-25 or A200-25


YS-9S


N-V346 or N-1346


1029-3B or I029-3B

My latest project is working on restoring brake disks. For now I have a NOS K1 disk until I can replace it with a correct restored one. I made a special tool for grinding the disks on a surface grinder.


I’m still experimenting but here’s where I am so far. Before…


…and after.


If you’re interested here is a thread that shows a little more detail about what I’m doing starting at reply #45.
http://forums.sohc4.net/index.php/topic,175601.25.html

What do you have for date codes on swing arms? I didn't find numbers that looked like date codes. #97 has a 6, #576 has an 8 and #1990 has a 23. I guess #97 could be a 6 or 9 but oriented the same way as #1990 it would be a 6. I'll post some pics when I get a chance.

That's the part number that's in the early parts manual and the later CB750-K2 manual.  So it appears that the same part number is available in either 17mm or 19mm. It sure looks like 19mm in the pic. I did send the seller a question so we'll see. I just assumed that 19mm would no longer be available. That's what you get for assuming. Thanks KP.

I just discovered (or maybe rediscovered) that #97 has a 19mm hex on the front turn signal stems (later are 17mm). Steven asked me about them and it jogged my memory. I had kinda remembered that there was something different about the stems on 97. The problem is that I was missing one of them so back then I decided to use the 17mm version.

I'm looking at the one I have and I could probably make one from scratch with too much difficulty. The biggest problem would be matching the knurling. It also would not be too much trouble to make them out of newer stems. Just an easy lathe job of turning off the nut and then copper brazing a bigger nut on. A minor problem is the nut is a little thicker but could be machined off. After chrome plating you would not be able to tell the difference.

I couldn't find a reference to this on the site. So do we have any idea how rare this distinction is? What VIN was it used up to? So is this a sought after part?

Thanks for the compliments guys. No, I am not a painter. It was done by Vic World's painter. His name is Blake Conway in Vista California. His number is 760-732-3950 if you would like to contact him. If you do tell him I said hi.  

Is your swing arm original to 97.

To accurately answer your question I have the swing arm that was on 97 (with the skinny markings). I have no reason to believe that it wasn't the original. Unfortunately the one that is on 97 now is the one from 1553. It was in much better condition than the one from 97 and looked the same to me (I did not notice the difference in the markings) so I decided to use it instead. Now that I'm older and wiser  I realize I should have used the original. That will be one of my next projects. Does anyone else have examples of the skinny marks?

I have no record of this but I thought that production ran from June to September 1969. Am I mistaken?

So are we saying that production ran from March until September?