Honda CB750 Sandcast

Restoration of Sandcast #97

markb · 814 · 327534

Steve Swan

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No one should ever feel they are a pest.  This is how we all stay fresh and learn, by sharing.

It's hard to imagine the spacers would never have been on 97's frame and it APPEARS there is paint chipped from the spacers being removed........... ?  The only caveat to "no spacers" would be 97 is the earliest frame we have seen and we know there are differences between vins, but it seems doubtful the spacers should not be present.  These cases is where BB member "concensus opinion" is great.

232's horn mount was bent rearward from perpendicular, not sure why, as the horn was undamaged and  intact.........

And, 232's steering damper gusseting was also bent, likely because 232 appeared to have taken a left hand hit to the steering head.  It might be a good idea to check the vertical orientation of your steering neck while the frame is bare, setting up a long shaft through the neck to compare the vertical plane's perpendicular trueness to the frame's horizontal plane.  232's neck, looking from the rear, was off perpendicular by about 2-3 degrees and required straightening.



Wayne

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Mark
Why not shoot APE a message and see whet they have to say on your crank? I'm sure they can grind it, spray weld and nitrate it and it will be as good as new. (maybe even better as they will balance it perfectly) They might be able to find the markings for the rod journal size as well which would alleviate the concern about matching rod weight to the repaired journal size. (vibration issue) Even if they can't it looks like it can be figured out without too much trouble.

If you would like some pics and measurements from my frame of the horn mount let me know. I'm hoping to get over today to pass the info you gave me on the side stand to my welder.

http://www.aperaceparts.com/crankwork.html
« Last Edit: January 11, 2011, 02:37:09 pm by Wayne »
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kp

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Pest ??? You're no pest If it wasn't for your posts on VIN 97 we would be back in "boring boring" land, still be as ignorant about these variations as we were 6 months ago and not have had the involvement of the members both old and new.
Keep it coming my friend ....................... I look forward to the new posts on a daily basis
As for the rear frame fender mount and horn mount, I'd agree with Steve. Seems they are not standard in their current form so go with your gut instinct
Yibbida yibbida ...... I'm outa here ...............  ;D KP
PS Did you check that downtube frame gusseting  ???
Yabba Dabba KP


markb

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OK.  I really appreciate everyones excellent input.
PS Did you check that downtube frame gusseting  ???
Not yet but I'm planning on machining those missing posts tomorrow night and will check it out and try to get some pics.
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 now have one opinion on the crank for E100.  This guy is pretty knowledgable about cb750's, he used to build and race them back in the 70's.  He said run it.  Most important he said was that the crank pins (rod journals) looked fine and that they are doing more work because of the alternating forces than the mains which are just rotating.  Seems to make sense.  He said he would just drill out the plugs and weld up the holes after cleaning them out.  I decided to make another attempt at removing them first and get another opinion about the mains.  I think I'll talk to Tom and Mark and maybe APE.  If at all possible (and practical within reason) I'd like to save this crank.
Just a comment about what Vic would do.  And this is in no way a slam against him, he does some of the finest restoration around.  I'm only guessing on the carb recall that ashimoto cited, but he probably doesn't try to restore that to original for a couple of reasons.  The first being a safety and liability issure, and the second being a cost issue and lastly being able to find the original parts.  Another example is I have talked to him about using Lotus Root exhausts on his early sandcasts and he doesn't because it pushes his selling price too high.  They're expensive enough with the no number pipes.  My point is, even though I'm trying to make 97 as accurate as possible, in the end I'm just like everyone else in that there is going to be compromises.  But in the case of the crank, this is one feature I'd like to keep if I can.
By the way I didn't get to the frame last night, it may have to wait until the weekend.
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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By the way ash, and I hope this is obvious, my comments about Vic weren't a slam against you either.  In fact it was an interesting point to ponder.  And just because you're not a sandcast owner doesn't make you any less qualified to suggest ideas.  I appreciate them all.
Thanks,
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?)


Steve Swan

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Vic's restorations are absolutely exquisite.  

The pressure Vic operates under (which we do not have) in perfoming his restorations, Vic has a business to run and liability to consider.

DITTO MARK'S LAST POST.


ashimotok0

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Hi Mark - of course I didn't think you were having a go at me. Hat's off to you guys, as it's really difficult getting my UK '69 K0 correct (ChrisR is not too far from me and has been a great help), so early Sandcast's must be an absolute nightmare to get correct (not to mention the expense!!) Even with the K0 though I think I am getting obsessive - trying to get the electrics correct. Presently I am replicating the K0 battery braided ground wire and making my own end terminals because I don't believe the complete cables Yamiya sell are correct.

see the show so far:-

http://i697.photobucket.com/albums/vv340/AshimotoK0/AshsCB750K0ElectricalrefurbsV1.jpg



Be interested to see how you tackle the alloy parts mark - your K0 restoration threads on the finish of your fork sliders on the SOHC4 site were really informative.

Re: Vic World - hats off to him too - making a living at restoration must be really difficult

Cheers!  Ash
« Last Edit: January 13, 2011, 03:54:41 pm by ashimotok0 »


kp

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Mark I own VIN969 and haven't started the rebuild of this yet but for the last 5 years I have been procuring as many NOS parts for this bike as I can. It will be almost a New bike once restored but I have retained as much of the original as I could. About six months back I bought a third sandcast which is a very low VIN. This bike is relatively unmolested and it is my intent to keep all the original parts with this bike(well as much as possible). If the side covers are cracked they will be repaired and reused, the instruments will be cleaned up and reused, master cylinder, switches, wiring etc etc will be cleaned up and reused. If my crank needs repair then so be it. I suppose what Im saying is I would rather have a repaired original part on a low number VIN bike
I like the way you are approaching your restoration in that you are attempting to retain originality. If I was to buy a restored low VIN bike and I removed the alternator cover I would expect to see the correct bolt. Sure it may cost a bit more but if you were of a mind to sell the bike one day, you can put hand on heart and attest to what is original fittment both seen and unseen.
I know some of us are becoming quiet anal (I put my hand up to this) about the smallest detail changes to the model run and others could reasonably ask does it really matter as the part will not be seen. It is a fair question but not one I would ask. From where I sit, and as expressed by others, keep the crank. ;D
Yabba Dabba KP


kp

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My oh my Ash, that harness has come up a treat.
Yabba Dabba KP


markb

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Some good news, bad news.  Here’s the setup I used to tackle the oil plug screws in the crank; an impact driver, 1/2” to 3/8” adapter and a 3/8” drive 3mm hex bit.


Here’s what I’m trying to get out.


This is what it looks like when it’s out!


Yes, that’s part of the good news.  I actually got two of them out!


And here’s why they have to come out.  Not sure how well this shows but the hole is filled with black sludge.


The bad news is the sockets in the next two rounded out.  So for the learn-by-my-mistakes department, I think the first two went too easy and I pushed too hard on the next two.  I used a lot of heat on the first two and since they were probably Loctited in that probably made the difference.  The other part of the good news at least I know what size and style they are for replacement and how deep the hole is for drilling or burning them out.  At least I know I can get them out.
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’m ready to drop the #97 frame off for the welder to repair my side stand mount, straighten the horn mount and steering damper gusset.  I also machined the posts that are missing on the frame.


Once the frame is painted you won’t be able to tell they were ever gone.


While I’m at it I’m going to see if he can fix up the inside of the upper, front motor mounts on the other frame.  It’s kind of hard to make it out in this picture but it’s pretty chewed up, probably from the lock washers.


Here’s what it should look like.


I’m thinking I’ll probably get both of them painted while I’m at it to stop any more rust.
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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The frames are out for welding so I decided to work on getting all the black ready for paint.  When I got to the oil tank I had another surprise.  There’s a pretty good size hole rusted through.  It wasn’t that big to start with.  Just a soft spot and that’s how big it got with just my thumbnail.  I haven’t decided if it’s repairable or not.  I think I should try removing the internal rust to see how bad it is first.


Another option is to use the tank from 1553.  I compared the two and there is quite a difference in the welds on the left side (in the picture).


Here’s a close-up of 97.  It actually looks like a repair to me.


See how smooth the seam is on 1553.


They both smooth on the other side.  Here’s 97.


And 1553.


I looked for a date stamp and couldn’t fine one on either one.  Is this the area it should be, on the backside of the rear upper mount?


So except for the crappy weld on the left side of 97 they appear to be identical.  Does anyone think this is correct?  Should I just use the tank from 1553 and take care of two issues?
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?)