Honda CB750 Sandcast

Restoration of Sandcast #97

markb · 814 · 326410

Steve Swan

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markb

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Mark, did it appear any penetrant made it the length of the split pin ?
Yes, the pin was wet along most of the length.

Mark, I would get the cases hot tanked and Ultrasonically cleaned to avoid blasting with anything, at least on the inside.
Supposedly the soda (baking soda) does not alter the surface either and can be rinsed off with water and leaves no residue.  I've seen a couple of threads about it on the SOHC4 site.  It looks interesting.  The ultrasonic cleaning looks interesting too and seems like it would be good for making sure the oil passages are good and clean. 
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?)


Steve Swan

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I've seen soda blasting videos, but have no first hand experience.  Th good part is the soda media is water soluble.

E100's oil passage galleries being clear are a concern.

I don't know anything about ultrasonic cleaning.  

Does u.s. clean the inside of long small galleries with angles as thoroughly as the outside surface ?

If u.s. DOES clean galleries, seems like u.s. is  the  way to go.  No matter what, as dirty as E100 is, patency of the galleries will need to be tested before engine assembly begins.

Looking at the pics you've posted, appears 97's side stand has non-factory weld beads ?

Good to hear the penetrant made it the length of the pin.


Wayne

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I figured just the mention of Soda Blasting would get things going. I have read a lot about it, know people who do it for a living but have no first hand experience because I have yet to use it. Here's what I do believe to be true:

If you ask 10 different people how to use it and how to neutralize it after you blast you will get 10 different answers.

There are products out there that "neutralize" the soda but does that mean it's gone? Those in the know use vinegar, soap and water. Then rinse, rinse, rinse. Water alone does not remove the soda from the material you blasted. The problem still lies in that any residual may not come out with the conventional methods we use to clean crankcases etc. ie: solvent based products. I think a look around would disclose that the guys putting together rare engines and doing restorations are sticking to the hot tank method combined with ultrasonic cleaning. Any good Automotive Machine Shop will offer the service and it's not expensive. I think I would go that route rather than blasting the insides with anything and see how it turns out. Just my 2 cents.

I do plan on cleaning my carb's with a small handheld unit though. If you don't neutralize it, the finish is preserved by the Soda for a longer period of time.
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kp

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I've recently had a tank, air-box and frame soda blasted and can sing it's praises. The frame had to have a little grit blasting in a few areas but came up a treat. There is no rough surface left as a result of grit blasting rather you end up with a dull finish and no sanding required to knock back the sharpness left from grit.
I tried soda blasting as I was told it was the way to go for removing paint from the plastic parts. After talking with the guy who owned the business I tried those 3 items. The removal of paint from the air-box was amazing and left a finish that looked like dull paper. Very safe form of blasting from my experience and you clean up with water. The thing I was impressed with after the air-box was done was a fine crack was exposed which I wouldn't have otherwise have picked up

Cleaning of galleries is something any form of blasting won't do well. Vapor blasting does clean the larger galleries but nothing beats ultrasonic cleaning. Carb shops use the process as does the Health industry. There are any number of You-tube videos out there. The only problem is finding someone with a big enough tank. Pics to follow KP

Vapor blasting finish


« Last Edit: December 18, 2010, 01:07:49 am by kp »
Yabba Dabba KP


Wayne

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Boy, we're really hijacking Mark's thread here. Maybe we need to start a Soda Blasting discussion. Like I said, ask 10 people you will get 10 answers. This page about wraps it up. I have seen hundred's and hundreds of cases where cars peeled because the stuff wasn't neutralized properly. There was one video floating around where the guy was peeling the paint from his restored Charger with a bondo applicator.  :( Again, since I can't move individual posts let's start a new thread if there is to be further discussion on Soda Blasting or the link. Don't want to digress too much on Mark!

http://www.crankshaftcoalition.com/wiki/Soda_blasting
« Last Edit: January 09, 2013, 08:10:03 pm by Wayne »
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markb

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No problem on the "hijack", I asked for comments, but yes, a soda blast thread would be great.  Better yet include the U/S and other cleaning methods too. 

For cleaning out the oil passages, besides using drill bits by hand in all the straight shots, I plan on squirting everything I can get at with degreaser and then take it down to the car wash.  It's amazing where water shoots out when you put the high pressure nozzle in any of the holes.

Wayne, did you see Steve's comment about my side stand mount?  Maybe you shouldn't be using my pics for your repair.  I'm going to compare it to the one on 1553.
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

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Yes, I saw it Mark. Steve and I were swapping a bit of info so I could best figure out how to repair mine. Your's at least looks like it's located in the right spot.  :)
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markb

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Steve, you are right.  I looked at 1553 and it is way different.  The first clue should have been that the paint looked different around the mount.  Doh!  It must have been repaired at some time.  Wayne, it might be located in the right spot but not at the same angle as 1553.  Crap!  From the side the mount on 1553 looks like it is perpendicular to the frame.  One of them is obviously located incorrectly.  I don’t think I can get a good shot of 1553 until I get the exhaust off.  But when I do I will try to take some pics.


Here’s another shot from the back side.


And another angle.


I wasn’t planning on tearing 1553 down at this time but I might have to so I can bring both frames to a welder to make it right.  Of course I want to confirm that 1553 is correct.  In the meantime does anyone have any pics of this area that they could email? 

Sorry Wayne.  I had no idea that mine was out of place.  Come to think of it, the bike did seem to be tilted too far but I knew the stand was loose because the fork on the side stand was bent open.  Obviously don’t use my pics to help repair yours.  I guess this is one advantage of this site and running a thread.  I have many sets of eyes to help me catch these things.  Thanks guys.
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?)


Steve Swan

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Actually, Mark, Wayne mentioned the glob to me.  I did notice the weld looked 'off,' but i will admit, i am not paying close attention to detail..............  my bad   :(

Anyway, i do not have the engine in 2157, so need be, i can roll it out of it's hole and get some pics of the lug.  Let me know, as you & Wayne are in the same boat.  This breakage HAS to come from people sitting on the bike with sidestand down.

As Wayne and i were talking, i don't know what or any diffs there are between early, middle or late sandcast s.s.lugs.  I do know "K0" gusseting is heavier and there are differences between early and late "K0" gussets as well as frame joints.  I know there are differences between the gussets/joints on 232 and 4363.  What i don't know is what diffs may exist on late sandcast and early "K0" or what diffs may exist beween early to middle to late sandcast.

It's difficult when one cannot have an early, middle and late production completely dis-assembled, side by side, in a large room.  I guess that's where painstaking notes might help, but even then w/o having the different models side by side, would not know what diffs exist.  Would be nice if you could dismantle you 1553 and compare to 97.

On soda blasting, is that a process that uses water?    Or could i use the soda blast media in my cabinent blasting set up ?  I would agree w/ Wayne, the guys who are restoring these rare expensive cars use the u.s. to clean things up.


Wayne

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Anyone have CAD Inspection/Reverse Engineering software??  ;) That, the tool to go with it and we're off to the races! Seriously though, if anyone has a stripped frame that will help us out we should be able to get these tabs bang on given some key measurements. The guy who is welding for me says it's a piece of cake to fix but he needs to know where to put the tab.
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markb

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Steve, I believe the soda blasting is dry.  I saw a homemade setup where someone put a slit near the end of a hose to insert an air nozzle and put the other end in a box of baking soda.  That was pretty much it.

I was thinking I might use the cylinders off 1553, maybe other parts too so I might as well start tearing it down.  No rush getting the frame painted on 97.  If my welder had the two frames side by side I'm sure he could make them match.  Seems like I've been tearing 97 apart for months (I guess I have) so it might be a while before I'm to that point.  I need to sleep on it and then get organized before I start another tear down so I don't get everything all mixed up.

By the way, I'm very interested in the US cleaning for the cases.  What kind of shop would have that?
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?)


Steve Swan

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I'm GUESSING either performance, restoration, aviation, marine shops/services could advise on sourcing u.s.  Maybe an internet search could yield results.

These guys http://highmountainclassics.com/ are North America's premier Bugatti restoration service, only 20 miles from where i live.  I'm guessing they know something about u.s.   I'm also guessing the Twin Cities has someone in the area who knows about u.s.


kp

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I have 2 frames I can get at 969 and 1683. Just tell me what I have to do. KP
Yabba Dabba KP


markb

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I going to tear down 1553.  After I do I'll post pics of the side stand mount to confirm that it looks correct.  If so I'll bring both frames to my welder and have him repair 97.  So nothing to do for now but KP and Steve, when I post my pics maybe you guys can give me an opinion about the correctness of 1553's mount.
 
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?)