Honda CB750 Sandcast

Restoration of Sandcast #97

markb · 814 · 285337

Steve Swan

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I remember when automotive crankshafts used to be "built up" (welded) then reground and re-trued.  I don't know if this practice still exists or not. 

This company is in Minneapolis, maybe they could offer repair, advice or referral - http://www.crankshaftsupply.com/crankhp.htm


markb

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I remember when automotive crankshafts used to be "built up" (welded) then reground and re-trued.  I don't know if this practice still exists or not. 

This company is in Minneapolis, maybe they could offer repair, advice or referral - http://www.crankshaftsupply.com/crankhp.htm
I found that company too doing an internet search yesterday.  I haven't had a chance to call them yet but I wish I had known about them before, they're only a few miles from me.  I haven't given up yet and will definately check them out.

Mark, that is bad news. Better that you had it checked though. If you really want to salvage that crank perhaps a company like Gleason can fix it up. I thought APE would have offered services like this.

http://www.gleasonengineering.com/process.php
Looks like these guys make the machines that grind the cranks.  If the other lead doesn't work out I will call them too.  They're only a couple of hours away.
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?)


markb

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I got the crank back from APE last Friday and dropped it off today at Crankshaft Supply.  It's too bad I wasted almost 8 weeks on it, but I should hear by tomorrow if they can (or will) do anything with it.  There hasn't been much else going on with this.  Too busy with work but I at least got 5383 and the early diecast out of storage.  Working on getting them ready to ride.   :)
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?)


kp

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Mark, I was so excited with the post I couldn't wait to hear what you'd done. :P Alas we are going to have to exist on bread and water for a little while longer  ;) Hope they can fix that crank.
Yabba Dabba KP


markb

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I’ve finally got a solution for the crank.  Out of the nine journals, four were fine, no pitting and in size.  Three had some pitting in the center of the journal but were also in size.  The repair guy said it would just be a pocket to hold extra oil and isn't an issue.  The last two (one rod journal and one main) had the most severe pitting and varied more than .0002” (.005mm) across the width of the journal and smallest near the edges.  Those two are getting repaired.  Should be done next week and cost me about $350.  More than I’d like to spend but I’ll feel good about running it.  Once I get it back I’ll Plastigauge everything to make sure everything looks OK.
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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That's what i've always heard, as long as the journal is within tolerance and cam lobe face not 'flattened', simple pitting retains oil and of no functional concern.


markb

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Sorry for the lack of posts.  I've been really busy and I finally got the crank back last week.  It looks really good.  Here's a before:


And an after:


Now to plastigage the bearings.  :)
« Last Edit: June 23, 2011, 05:28:13 pm by markb »
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?)



kp

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Wayne

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Looks great Mark! Should be smooth sailing to get that crank fitted now....and with peace of mind.  :)
[size=


ack3r

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I picked up the painting this past week.  Everything looks pretty good but it seems glossier than I remember.  The painter swears it’s the same as my other bikes so I guess I’m good with it.  


I guess my only complaint is the paint looks like it got a little heavy on the VIN.  It’s really hard to get a good shot when the paint is so new and it’s more readable than it is in the pic.  I’m not real pleased about it but I think I’ll let it go.


I didn’t do the top fork bridge yet because I think the paint is less glossy than the rest and didn’t want to do it in this batch.  But I can’t remember if the lower part of the fork stem is glossy like the frame or more matte like the top fork bridge and my other bikes are in storage so I can’t look to compare.  Anyone know?


Hi,
I like Your work....
I would to receive some information regard the paint of frame.
I'd read In some web site, informations regard resistent  paint for the frame.
The possibility are two, polyurethane (bicomponent)  or epoxy.
For much of site web, the polyurethane paint has more resistant to gasoline and to abrasion/collision.
Can You help me?
I would to have more information regard to original honda paint.
Is true that the master cylinder and other parts,  must be painted with epoxy paint?
I'd read that epoxy paint is strong with brake oil.
Thanks for the patience

Maurizio

p.s.
would be nice to have a section dedicated to painting
« Last Edit: August 26, 2011, 04:55:25 pm by ack3r »
Cb 750 Four k0 1970  "restoring ended"
Xr600r 1986 ''work in progress''
Cb 750 Fa 1980
Vespa Vba1t 150 year 1959


kp

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ps.
would be nice to have a section dedicated to painting

Maurizio
There is a section devoted to paint and badging  ;) KP
Yabba Dabba KP


ack3r

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ps.
would be nice to have a section dedicated to painting

Maurizio
There is a section devoted to paint and badging  ;) KP


Hi Kp, I've seen .
Please can you show me, the better topic regard the paint of frame?

Bye
Cb 750 Four k0 1970  "restoring ended"
Xr600r 1986 ''work in progress''
Cb 750 Fa 1980
Vespa Vba1t 150 year 1959


markb

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I have a painter that does the frames for me.  They were painted with a single-stage black urethane paint.  My painter reduces the gloss a bit to make it look more authentic.   
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?)


ack3r

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I have a painter that does the frames for me.  They were painted with a single-stage black urethane paint.  My painter reduces the gloss a bit to make it look more authentic.   

MMhh, I don't know this paint.....Is better of Polyurethane?
I know that polyurethane paint is very strong to gasoline, but I want to ask in my town regard your system.

p.s.
Can You give me the brand and model ?

thanks
Cb 750 Four k0 1970  "restoring ended"
Xr600r 1986 ''work in progress''
Cb 750 Fa 1980
Vespa Vba1t 150 year 1959