Honda CB750 Sandcast

Here we go! Restoring 576/748

Wayne · 180 · 71146

ashimotok0

  • Sr. Member
  • ****
    • Posts: 322
    • View Profile
Cheers KP !! Sometimes don't know if I ramble on too much !!!

Anyone know where to get small quantities of the silicone impregnated white glass woven sleeving of various sizes. I have found loads of places which make it in the UK (Lancashire seems to be popular) but they want to sell me miles of it. I am trying to get samples, as I run my own small electronics company so  I have a legitimate reason to request. I need some for the alternator  sub-harness, points lead and oil pressure switch.

For example:

http://www.birchvalley.co.uk/uploads/Non%20shrink%20Vidaflex%20111.pdf

BTW you know those three little bits on the Regulator. If these are not too bad, then leave them in a mixture of neat bleach and biological washing powder for an hour or so and they come up a treat.

Back to the connectors I also hear that the Yamiya pack of them are good and good value.

On another subject I was thinking of getting some graphics made on a backing sheet of masking material printed with the markers and 9 figure around the Tacho face. You could use this to mask the red line - respray the red-line and then pick off with a pin whist the paint is still soft. What do you  all think?.My gauge faces are perfect apart from the red line on the tacho. Lecram's faces seem really good but it's a shame to have to replace perfectly good faces because of the red line fading. Anyone know a font size that is a match for the 9 figure.

My mate is analysing the rubber dampers in the primary drive  sprocket assembly. I have three virtuallly NOS  Genuine Honda ones from KOS on the SOHC4 site for this analysis. As soon as I have the analysis and microhardness specs, my other friend who runs an automotive rubber moulding company near me  (and Goldwing owner & CB750 Cafe bike) is going to quote me on the tooling and moulding of them. A German forum already sells sets of these but will not sell to nonmembers and will not share the tech details.

Rambling over back to the Cider!!!!!!!!!!!!!!! :) Cheers Ash

Postscript -- Just noticed that the link I gave for silicone/glass sleeving advertises cut lengths of the stuff !! Will phone 'em Monday.
« Last Edit: November 26, 2010, 06:41:10 pm by ashimotok0 »


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Should be pulling the engine tomorrow or next day. I'm just getting all of my parts ready that will need to be blasted and painted black. I found a pretty decent mainstand. (mine was missing) What is the concensus on the brace? Should I leave it or remove it?

What about the Triple Trees? Same paint as frame? Powder Coat? Someone said to me that a sandcast should not have any PC but I have seen PC trees out there.

[size=


hondasan

  • Administrator
  • Sr. Member
  • *****
    • Posts: 379
    • View Profile
Hi Wayne,
At your VIN, the original mainstand would NOT of had the strut on the left hand leg, so personally I would remove it.

Whilst I have so far used powder coat on my frames, mostly because I want to be able to ride my bikes without worrying about stone chips (and the guy I use does not put too much on so it looks like plastic coating), the triples trees I have always painted using rattle cans - gloss black on the lower tree and a satin black on the top tree which I believe  to be the Honda finish. Just my view.

Cheers - Chris R.
Chris R.
302/338


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Hi Wayne,
At your VIN, the original mainstand would NOT of had the strut on the left hand leg, so personally I would remove it.

Whilst I have so far used powder coat on my frames, mostly because I want to be able to ride my bikes without worrying about stone chips (and the guy I use does not put too much on so it looks like plastic coating), the triples trees I have always painted using rattle cans - gloss black on the lower tree and a satin black on the top tree which I believe  to be the Honda finish. Just my view.

Cheers - Chris R.

Thanks Chris. I figured the brace should come off, just thought I would check. From what I have gathered I will be doing the frame and frame components in a single part Urethane, about 90% gloss. If you say so, it's gloss on the lower tree and satin on the upper.

I can only assume they flattened out the upper tree to tone down any reflection when viewing the gauges. Why the high gloss on the lower tree though? Why not the same as frame or even the upper tree for that matter? Just curious. Don't know why I can't just "do"! Always have to know why for some reason!  :)
[size=


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
In the home stretch as far as taking the old girl apart. I'm in the same boat as Mark as far as Fork Tubes. Looks like I'll be giving Forking by Frank a call!



The finish on the lower Cushions is just crazy! In areas they looked polished, in other areas it looks like a think film of (plating??) is peeling. Around the mounting bosses where I wiped a pile of oil sand dirt off is what I believe to be the proper finish.



And of course, now the ugly. I have a crack in one of the mounting boss's. No big deal to repair, just something else to do! Perhaps Santa will make my life easy and find me a correct set of NOS lower Cushion's for this sandy!  ;)



A little bend in the right headlamp ear. Again, no big deal. Candy Red Paint shows through in the lower area.



Hopefully tomorrow the engine will come out and I'll get all the black pieces sorted and ready to send out for blasting and paint. Can't wait to have everything cleaned up so I can start moving in the other direction!
« Last Edit: November 28, 2010, 03:34:23 pm by Wayne »
[size=


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Here's another anomaly with this bike I haven't figured out. Note the seat pan shown is a later pan. That little white tag you see is a tag with the original owners name on it. Assume it was put there when he got th eoriginal re-covered. We have identified the 10 hole on up to bike 1081. How could 576 possible have wound up with a later pan from what appears to be day 1? I'm guessing everyone will say that I should buy a 10 hole/red foam to make it authentic and I probably will, but this one has me somewhat puzzled.

(I guess there's a chance the Dealer changed it for whatever reason prior to sale)

« Last Edit: December 08, 2010, 09:48:16 pm by Wayne »
[size=


hondasan

  • Administrator
  • Sr. Member
  • *****
    • Posts: 379
    • View Profile
Wayne,
Re. finishes on the frame and upper / lower trees - just my observations from the five or six sandcast / K0's I have experienced, plus some NOS triple trees I have. Would welcome opinion from others out there.

In my experience, it doesn't matter how much we think we know, there is always more often contradictory evidence to take in - 40 years of aging / owner polishing / re-finishing can lead us astray too!

Cheers - Chris
Chris R.
302/338


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Thanks Chris. if you guys can be lead astray imagine a newb like me!  ??? ??? Oh well, we'll give it our best shot.

I wiped down the underside of the lower tree. I can see where it is more glossy than the upper. So I guess it's a matter of figuring out if it is glossier than the frame or the same? (90% gloss)

Surprisingly the door to the lock came open with no effort. The tumbler will move around with my finger but it does not match the ignition key I have for the bike. The tumbler is a T4997.

The number in the casting is "M1" with a "J" on the other side.

[size=



Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Well I finally got around to getting engine out of the frame. Thinking ahead and knowing I don't have a lift I wanted to come up with something that I could rely on that would be damage free during the installation process. Everyone has see the trick of laying the frame on it's side with the engine supported by heavy blankets etc. Well I went a step further and made a mold of the end of the engine using expandable foam. It worked great. Two of us were able to lift, rotate and set the frame/engine on the mold side. I removed the last two mounting bolts and we wiggled the frame over the motor with ease. The motor stood there in the mold until we were ready to heave it onto my workbench for further surgery.

My crude but effective mold:



Engine 748 on the bench and ready for a refurbish:


[size=


markb

  • Moderator
  • Hero Member
  • *****
    • Posts: 1249
    • View Profile
Clever idea!  I wish my engine looked half that good.  Hopefully the inside of yours looks better than mine does too.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
I hope so as well Mark. Not a drop of water in the oil. It was like new and compression was great on all cyl's. I can't wait to get into it. Have one broken bolt to get out of the head for an exhaust flange. I already loosened all of the rocker cover screws. They have been soaking in Liquid Wrench for a while. They all came loose with just a screwdriver.  :) I'll pop the cover off tomorrow.
[size=


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Found some time tonight so I popped the rocker cover off. All went well with the exception of one frozen screw. All the others came out with ease. Strange.  ??? I just drilled the head off to avoid breaking it and removed the cover.

Here's what I found. I wiped nothing off...notta!  :) Note what look like felt pen markings on the camshaft holders. I'm guessing perhaps some was in there for a related Service Bulletin?



A closer shot:



And the cover. I couldn't believe how clean it was. I never wiped a speck or a drop off for this pic.



And a close up showing what I assume may be a date stamp???

[size=


Steve Swan

  • Hero Member
  • *****
    • Posts: 2705
    • View Profile
    • cb750sandcastonly.com
Beeeuuuuteeeful, Wayne ! 

Somewhere in the BB there is an article on the date stamping methodology, i annot remember the exact details, but your dates stamp's interpretation is 44th year of the Emporer's Reign, 4th month and 8th day.

April 8, 1969


Wayne

  • Administrator
  • Hero Member
  • *****
    • Posts: 1044
    • View Profile
Thanks Steve. Any thoughts on what look like felt marker strikes?
[size=