Restoration of Sandcast #97

[Wayne]

Mark
After thinking about it, if you do want to change your deck height because yours was cut down it would be done via the base gasket. You can get different thickness's here:
http://cbrzone.com/gaskets.html

[markb]

I had stuff to do last Saturday so I was only able to work about 4 hours on Sunday.  By the way, that brings me to about 66 hours on this project including the time to drive to Oklahoma and back to pick it up, looking on line for parts, teardown, posts here, everything.  I’ll be interested to see what I have into it when it’s done.  I don’t think I’m going keep track of the money though, it would probably make me quit.  Maybe after I’m done with this project I’ll take up a cheaper hobby like horse racing.

I did get the cylinders off and the pistons come out quite easily after several cycles of heat and soaking with Aerokroil (highly recommended by Steve Swan, it seems to work really well).  The #1 & 4 bores don’t look so good and the #4 piston has some scuff marks on the piston pin sides of it.  I’ll post some pics after I get them cleaned up.  I didn't get around to measuring the c'bores but it sure looks like less than .93mm.  Still weighing my options on what to do with the oversize cylinders and pistons.

I’m having a hell of a time getting the starter motor out.  After a couple of soak and heat cycles I’ve managed to move it about 1/8” but I don’t want to tap on it too hard.  I did get that broken rotor cover screw out.  After more heating and soaking it came out easily with no thread damage.  I also got one stud out before I ran out of time.

Here’s a question for the restoration purists, how do you feel about using the APE heavy duty studs?  I’ve used them on my last two projects because I wanted to do everything I could to make sure I don’t have oil leaks.

Here’s where I’m at.

[Riccardo]

Hi at all,

Steve and Chris,.... ....please note the sign where was the DOT sticker on the upper cranckcase.

Those cases do not was damaged by chain.

The owner has found the dot on the upper crankcase?
What colour was?
Red or b.green?
The sticker colour match with the colour of the bike?
Or it was lost?

Regards

Riccardo
 

[ashimotok0]

Be interested to see how you get on taking those two short centre studs out Mark!!

Keep up the good work!

[markb]

I’ve had a couple of comments about the white dot on the top of the upper crankcase.  If you look at the first pic there’s actually another smaller irregular spot near the left, top mount.  Are these marks some kind of factory mark?  Is the irregular one just a mistake?  The round one looks pretty deliberate.  I’ve heard that on earlier sandcasts there was supposedly either a red or blue/green dot to indicate the bike color.  I scratched on it to see if was another color underneath but it’s definitely white all the way through.  Could it have bleached out?


Here’s a close up of the round one.  It looks like paint and it’s fairly thick, I can feel an edge on it.  It looks a little wrinkled too.  Like it was maybe applied with a dauber.  If it is a factory mark I would like to duplicate it.  Anyone have any theories?

[Wayne]

Mark
I'll post a picture of the "dot" on my crankcase when I get a chance. Mine is definitely blue/green. I know for a fact that the bike was red when purchased. Unless mine is an anomaly that blows the red bike, blue bike theory out of the water. I can't imagine why engines would be designated by color anyway. (except that red bikes just plain go faster  ) Colored dots were used in automotive production as well. Perhaps a little research will turn something up.

[kp]

I had stuff to do last Saturday so I was only able to work about 4 hours on Sunday.  By the way, that brings me to about 66 hours on this project including the time to drive to Oklahoma and back to pick it up, looking on line for parts, teardown, posts here, everything.  I’ll be interested to see what I have into it when it’s done.  I don’t think I’m going keep track of the money though, it would probably make me quit.  Maybe after I’m done with this project I’ll take up a cheaper hobby like horse racing.

I did get the cylinders off and the pistons come out quite easily after several cycles of heat and soaking with Aerokroil (highly recommended by Steve Swan, it seems to work really well).  The #1 & 4 bores don’t look so good and the #4 piston has some scuff marks on the piston pin sides of it.  I’ll post some pics after I get them cleaned up.  I didn't get around to measuring the c'bores but it sure looks like less than .93mm.  Still weighing my options on what to do with the oversize cylinders and pistons.

I’m having a hell of a time getting the starter motor out.  After a couple of soak and heat cycles I’ve managed to move it about 1/8” but I don’t want to tap on it too hard.  I did get that broken rotor cover screw out.  After more heating and soaking it came out easily with no thread damage.  I also got one stud out before I ran out of time.

Here’s a question for the restoration purists, how do you feel about using the APE heavy duty studs?  I’ve used them on my last two projects because I wanted to do everything I could to make sure I don’t have oil leaks.

Here’s where I’m at.

Mark, I'm a purist and would use stock, BUT, If the eye don't see it then the purist cannot grieve.  KP

[Joe K]

Mark,

I think the heavy duty engine studs are the way to go.  I used them on my sandcast motor.  You can always keep the stock one to keep with the bike/motor.  I would rather use the heavy duty studs to possibly prevent oil from leaking in between the valve head and piston head.

Joe K.

[Joe K]

Concerning the dot on the rear of the sandcast motors.... does anyone have contact with the guys who gave the presentation of the inception of the CB750 at the 40th anniversary meet last year?  Maybe one of them may remember the reason.

Mark, maybe yours is white because it was a white sandcast police bike.  Even more rare.  Just kidding.

Joe K.

[Riccardo]

Hi,

the DOT is really a mistery.

In our previous email contacts, with Steve S. and Chris R., we have elaborated many theories:

1)the DOT was, on the line factory, the sign for the final colour of the byke, to create a balance of the colours or increase the production of the colour most needed by market, really we have seen until now only the red and the b.g. DOT;
2)for the theory of the owner/seller of a couple of crankases, appeared on ebay many months ago, he says that the dot was on the bike because the cases was damaged by the chain and returned repaired by Honda and this was the mark of the repair;but this man is the one who has a story about the DOT;
3)the doubt remains because we have seen red dot on b.g. bike and b.g. dot on red bike, sometime the colour of the dot match with the colour of the bike;
4)now there is also the withe DOT and the mistery is very total in this moment.

I think that the better think is ask suggestions by Bob Jameson & C.

[Wayne]

Riccardo and Mark
Although the dot may appear to be white I'm wondering if it didn't have some color pigment when it was applied. If you have a look at mine it is apparent that it was blue/green but as that goes away a white foil type surface presents itself. As I stated in my thread, 576 is a red bike and I can verify that right back to the original owner. It's a mystery. 

[Joe K]

I think that the dot is an adhesive/sticker of some sort of material that is white.  Honda probably had these applied with the red or blue/green paint.  Finally, applying them to the engine as identification for the final bike color.  Wayne and Mark's red and/or blue/green color has simply worn off as can be seen on Wayne's engine.

Joe K.

[Wayne]

I think that the dot is an adhesive/sticker of some sort of material that is white.  Honda probably had these applied with the red or blue/green paint.  Finally, applying them to the engine as identification for the final bike color.  Wayne and Mark's red and/or blue/green color has simply worn off as can be seen on Wayne's engine.

Joe K.

Joe
I think you are partially correct in that the substrate material is white with a color applied to it. At least in my case it does not coincide with the final bike color. My dot is Blue/Green. My bike is (was) Red. The Red color is documented right back to the original owner and clearly shows on all of the painted parts for the bike. 576 is a Red Bike with a Blue/Green dot.

Perhaps we need to move this to an new thread so as not to take away from Mark's work?

[markb]

After looking at Wayne's dot I agree that it probably had a color on it at one time.  Which color, who knows?  I don't mind the discussion here about the dots but starting a new thread may be helpful to attract other comments.  I can start one if I get a chance or if someone wants to, go for it.
Mark

[Wayne]

After looking at Wayne's dot I agree that it probably had a color on it at one time.  Which color, who knows?  I don't mind the discussion here about the dots but starting a new thread may be helpful to attract other comments.  I can start one if I get a chance or if someone wants to, go for it.
Mark

Any further discussion on the Dots will go here:
http://cb750sandcastonly.com/smf_forum/index.php?topic=383.msg2103#msg2103

Thank You.