Restoration of Sandcast #97

[markb]

I dropped the cylinders off at a local engine rebuilder to soak in their hot tank for a while.  Hopefully that will soften it up.  If not I think I'll try paint remover or the torch.

[markb]

I got the gasket off.  What a PITA.   


I had dropped it off on Thursday but they didn’t get it into the tank until yesterday morning.  They soaked it all day then scraped on it then soaked it all night and scraped on it again this morning.  Then they put it back in back in for the morning and scraped it one more time before I picked it up at noon.  They got maybe 50% off but there were a couple of scratches bigger than I liked so I decided to tackle the rest myself.  For $35 I was hoping they would be able to get more off than that.  I used some Permatex Gasket Remover and that seemed to help some.  I put it on and would let it soak for 15 minutes on one half while I worked on the other half and back and forth until I got it off.  It was a matter of shaving it off little by little rather than scraping.

I had to grind down one of my scrapers so it would fit between the number 1 and 2 and between the number 3 and 4 sleeves. 


I was tempted to try paint remover but I was at least making slow progress so I stuck with it.  I guess the only liquid that really worked was elbow grease.  It actually looks pretty good.  I don’t think they scratched it that bad.  It was still about six hours of labor total.  I’m glad that project is done.

[markb]

I haven’t posted lately but I have been busy with the holidays.  Even then I’ve managed to get a few things done.  Besides sorting through my parts for plating I got the cases, cylinders and head ready for painting.  Everything checked out OK on the head and the valves are lapped.  The cylinder is honed and ready to go.  Everything has been blasted, cleaned and masked.  I dropped them off at my painter’s last night and I should be able to pick them up tomorrow.

[markb]

Here are the finished products ready to assemble.
The cylinders:


I did put the head together before painting so I didn’t have to worry about dinging it up with the valve spring compressor.


Lower case:


Upper case:


Gotta love that number


Normally I’d be tempted to start putting things back together but I’m going to work on getting all the parts ready first.  I’ve got some smaller engine parts to paint too but at least I have the big stuff done.

[markb]

I decided to tackle the wheels next.  I figured while I was at it I would do the plating for #97 and #1553 at the same time so I’ve got both sets of wheels to work on.


It only took about two hours. 


One weird thing is a lot of the spokes were sticking out beyond the nipples on the 97’s rear wheel.  The other three seemed normal.  Now that I think about it maybe those spokes seemed a little tighter.  I checked both wheels and they’re exactly the same size as near as I can tell.

The rear rims are definitely the rolled rim type...:


… with the DID logo, the only marking on the rim.


I did notice one difference between the rims.  The rim on the right is off #1553 and appears to have some kind of coating in the center of the rim and 97’s doesn’t.  Any significance to that?

[markb]

Now for some interesting stuff.  I compared the rubbers between 97 and 1553.  The one on the left is off 97.  If you look at the lower left part of the rubber there seems to be a slight difference.  There is a slight curve on 97’s and more straight on 1553’s.  But I thought that rubbers on VINs before 302 didn’t have holes so it looks like mine have probably been changed.


So this got me thinking about the rubbers on my K0.  Instead of four wide and four narrow, they are the same size but symmetrical.




Checking in an early parts book shows that style.  I also seem to remember something about a recall on these.  Is it possible that the ones on my K0 would be correct originals?

So like I said, I thought this was interesting, but wait, there’s more!  I’m sure some of you have heard about 2-hole hubs and the later 4-hole hubs.  How about a no-hole hub?!  I didn’t notice it until I took out the rubbers but 97’s hub does not have any holes.


Anyone seen this before?  I’ve never heard of it.

[kp]

Mark, These discoveries are amazing KP

[cb7504]

Mark:
      The early rear hubs came with out holes and had the larger rubber bushings. The second version had two holes along with the large rubber bushings. The last version had four holes with four thin rubber bushings and four thick rubber bushings. From what i understand the holes were added to relieve brake dust build up in the hub. I am also unsure as to the vin cut off on the different hubs. The parts books i have shows vin number CB750-1044649 as a change in the rubber bushings. Marty K.

[hondasan]

No hole hubs are possibly the rarest of the rare early "features"! I have seen just one of these previously, and that was on a single digit bike.
I think you will find that the cush rubbers have been changed - there was a recall at some time I believe which affected these. Picture attached of original cush rubbers from #302, which changed to the symetrical ones as per your K0 pictures. Then a later change again to the type in #97 / #1553

Cheers - Chris R.

[markb]

So the earliest version was a no-hole hub with no-hole cush rubbers.    Great.  Now I have to try to find some no-hole cush rubbers.  Seriously, I'll probably settle for trading the ones from the K0.  One step closer to being correct I guess.  Unless someone has a set they want to sell.    Chris and Marty, thanks for all the interesting feedback.
Mark 

[markb]

I’ve got some progress to report although I had very little to do with it.  I decided to send out my gauges.  To me there are a couple of key things on a restoration and the gauges are one of them.  And these were definitely beyond my abilities.

They were pretty bad to say the least.  Here’s the speedo before…


…and the tach before.  Believe me, they were worse than the pictures look.


Here’s the restored product.


It was important for me to save the original cast housings since they are different on later models.  I had the NOS rubber cushions without ribs so that was really my only contribution.


Marcel den Butter (user name lecram on this site) in the Netherlands did the work.  Here’s his webpage:
http://www.cb750faces.com/webshop.php
I’m extremely pleased with the finished result and definitely recommend him.  He’s easy to work with and kept me informed every step of the way.  Thanks again Marcel.

[CB750faces.com (Lecram)]

Many thanks for your nice words, Mark. It was a great pleasure to do this for you. Especially the speedo was in a very bad condition. I am happy that I was able to completely repair the speedo as well with original Sandcast parts.

The internal mechanism as it came out of the speedo:


The internal mechanisme in parts. I kept the unique series 1 parts and added some series 2 sandcast parts which are the same as the first series:


All parts brought together:


Completed with the day trip counter

[markb]

Thanks Marcel for adding some additional history.

That's exactly why I delegated this task to the expert.

[markb]

I dropped off my parts for chrome plating today.  I should have taken a before picture but I already had it boxed up.  I threw in the fenders from my other sandcast too.  There were a few bends and dings in them and I figured it would help them do the straightening if they could compare them.  So it ended up being a pretty good size load.  I probably should have tried them out with a couple of parts first to see how they do but they came highly recommended and I saw some of their stuff.  Some of it was way too good for what I want but they seemed to know what I meant by dialing it back to a more authentic old Honda look.  I just hope they know what they're doing.  I don't know about you guys but these places scare me.  They always look disorganized with boxes of parts all over.  I don't know how they keep track of everything especially the little stuff.  I'll probably be having nightmares about a couple of double cut front fenders disappearing.  
Oh well, zinc next.

[Wayne]

I know how you feel Mark. The place that did my zinc was busy and very industrial. When I went to pick the stuff up they only handed me the large parts! No bolts small parts etc. After about 1/2 of sweating they found the rest of my stuff. I won't be able to go through that again with the chrome! My heart can't take it!