Topic: Sandcast #97 restoration

[zzpete]

Wow, your persistence and dedication are inspiring.

Carry on.

I'll second that! After seeing the inside of this motor I'm tempted to go out to my next project and fill the engine with acetone and ATF!! Then let it sit until March!!

[markb]

Sometimes the dog bites you and sometimes you bite the dog.  Tonight I bit the dog.  I got the spring pin out using a dent puller!  First I drilled out the center of the pin with a drill about .010” bigger than the standard tap drill for a #10-24NC thread.  It only went down about a ¼” before the bit got dull.  Then I carefully ran a #10-24NC tap in as far as I dared.  I got maybe 2-3 full threads.  If you haven’t hand tapped before, I don’t recommend it.  I’ve been soaking it and I put some heat to it and used a piece of bar stock to rap it on each side with a hammer a couple of times.  Then I took the collet off the end of the puller and put a #10 screw through it and screwed it into the end of the pin.  I also used a vice grip to squeeze the protruding part of the pin as tight as I could on the screw.  Then I screwed the puller onto the collet and applied more heat – I’m throwing everything I have at it.  I started with a couple of light taps and after a couple of hits I checked and it looked like it had moved a little so I kept at it.  Once it started moving it came about ¼” at a time.  Here it is just before it popped out.  The actual pulling only took about a minute.


Here’s the pin hanging on to the end of the screw in the puller.


Here’s the tool…


…and the hole where the pin was!  If I were to try it again I’m not sure I would try the tapping.  I’d drill it out enough so I could force the screw into the pin and then clamp on it with the vice grip.  With slot in the pin I think it would flex enough to clamp onto the screw and be less risky as far as breaking at tap.  For what it’s worth.  At least it’s out.  Thanks for everyone’s input.

[SOHC Digger]

Congratulations!  Vaguely reminds me of a doctor using forceps to bring a stubborn child into the world!

[CB750faces.com (Lecram)]

That's a smart way to get it out. I have struggling with that pin as well and this way seems to be the smartest

[markb]

Thanks guys.  Hopefully by the weekend I'll finally have everything removed from the cases.  Then I'll be ready for the cleanup.  I'm thinking of having the cases soda blasted inside and out.  Any comments?  For final paint prep I would probably do like I've done before and blast the outside with a very fine sand and then paint right away.  I've had no trouble with paint sticking on my last two projects and they look great.

[754]

 Your brave? tapping a hardened pin with innterrupted cut!!

 I should have mentioned if you got the end of pin red hot once or teice it would soften it, easier to tap.

 How about this, a small Jacobs drill chuck fastened to the slide hammer. This, or a proper collet , would compress the springpin slightly and relax part of its grip, allowing easier pulling.

[markb]

I didn't go far but I think I did push the tap to the limit.  I like all your ideas.  Especially the chuck or collet.  I hope I won't have to use any of them next time.

[y2kc0wb0y]

I know this sounds crazy but I've found success with actually tapping a pin like that in slightly more and then trying to pull it. Disturbs the bond and then you can pull it back. IDK just FYI.

[markb]

Another good idea.  I actually thought about that too but it wasn't sticking out very far the way it was and I didn't want to push it down any more that I had to.

[markb]

I haven't posted in a while but things have been pretty busy.  That and I got distracted with another problem.  One of the guys on the SOOC site had a side stand bracket that he had to repair and I sent him some pics of mine to help him out.  After a few of the guys looked at it I found out that mine had been rewelded and was in the wrong location.  A stroke of good luck there.  Not that I have to repair it but that I discovered it now instead of after the frame is painted and the engine is back in.  Here's a shot of it.  It should have been obvious that it had been rewelded because of the crappy weld and the paint is different in that area.  Fortunately I have another sandcast frame so I can bring both to the welder and get an exact repair.


I did manage to remove the remaining parts in the cases.  Nothing eventful there.  I'd like to do a hot tank dip and then ultrasonically clean them but I'm still looking for someone in the area to do the ultrasonic.  In the meantime I'll clean out all the threaded holes and oil passages as best I can.  Here they are.

[750essess]

A word of caution on blasting the insides. My 76 cb750 f cases had a coating on the inside. I noticed it when I used paint remover on the dis-assembled cases. Has not seemed to cause a problem removing the coating. I'm guessing it was to improve oil drain back. Not sure if early cases had the coating.

[René 衛星の]

I am astouned by the differences between the earlier bikes and the later ones (1970). I have been working with SOHC bikes since 1978, but I had not thought I could learn that much in just 30 minutes!

KUTGW (Keep Up The Good Work) Mark!

Cheers, Rene

[markb]

A word of caution on blasting the insides. My 76 cb750 f cases had a coating on the inside. I noticed it when I used paint remover on the dis-assembled cases. Has not seemed to cause a problem removing the coating. I'm guessing it was to improve oil drain back. Not sure if early cases had the coating.

I agree about the coating on the inside.  After considering soda blasting inside and out, I'll only be blasting the external, non-machined surfaces.  Everything else will be masked.

I am astouned by the differences between the earlier bikes and the later ones (1970). I have been working with SOHC bikes since 1978, but I had not thought I could learn that much in just 30 minutes!

KUTGW (Keep Up The Good Work) Mark!

Cheers, Rene

Thanks!

[754]

 I dont think the inner cases are coated, I believe it is a varnish/stain from the oil & heating/cooling cycles.. I could be wrong, someone with NOS cases can clear this up..

 Part of the charm/allure/mystique of sandcasts, besides being the first of that type of MC out of Japan, is the changes and evolution it went thru, over a short tun of 7400 bikes. I checked the CB5004 parts book, and could not find any parts unique to the first models. Same for Z-1s, few if any differences between # 17 and #11,000 ! Virtually the same bikes. On the sandcast 750 there is between 50-75 parts (or more) that are unique to that group of bikes.That makes them much harder to restore correctly, and in turn drives up price of parts and finished bikes..
 If I understand correctly, you are fixing your sidestand issues.. the other 69 frame you are using for reference? not cutting stand off, I hope?

[Greggo]

I checked the CB5004 parts book, and could not find any parts unique to the first models.

The seat latches were '71 specific...Very important

Thread Jack Over.

Great Progress MarkB!! 

[MCRider]

I dont think the inner cases are coated, I believe it is a varnish/stain from the oil & heating/cooling cycles.. I could be wrong, someone with NOS cases can clear this up..

SNIP

I agree. Anything that looks like a coating is stain from oil. I've seen NOS cases back when we would warranty them for chain breakage. Raw aluminum. My personal experience would stop with 1974 or so, but I would think that would have been noted in the many publications that have listed the changes from model to model.

Or HondaMan would know.

Been a long time so OCICBW, but I don't think so.

[markb]

Part of the charm/allure/mystique of sandcasts, besides being the first of that type of MC out of Japan, is the changes and evolution it went thru, over a short tun of 7400 bikes.  On the sandcast 750 there is between 50-75 parts (or more) that are unique to that group of bikes.That makes them much harder to restore correctly, and in turn drives up price of parts and finished bikes..
If I understand correctly, you are fixing your sidestand issues.. the other 69 frame you are using for reference? not cutting stand off, I hope?

You are correct.   I'm lucky to have the other early sandcast frame.  Welder says I won't be able to tell the difference when he's done with it.  And its partly because of what you said that there really is no other choice but to repair it and repair it right.  And FYI there are closer to 90 differences between early and late sandcasts.  Here's an interesting thread:
http://cb750sandcastonly.com/smf_forum/index.php?topic=217.0

Thanks for all the comments on the inner coating (or lack of).  It would be interesting to know for sure, but either way I won't be blasting the inside.

[MoMo]

I replaced an awful lot of 750 cases back in the 70's and to the best of my recollection the new cases looked like aluminum inside and out.  I remember we got paid 18.5 hours to do the entire case swap under warranty.  Keep up the good work...Larry

[markb]

I replaced an awful lot of 750 cases back in the 70's and to the best of my recollection the new cases looked like aluminum inside and out.  I remember we got paid 18.5 hours to do the entire case swap under warranty.  Keep up the good work...Larry

I probably have twice that just tearing it apart.
Thanks for the encouragement.

[markb]

I had little time tonight and didn’t feeling like tearing down on the other sandcast or cleaning the cases so I decided to tackle something easy like removing the rotor from the crank.  I’ve been soaking it in Safest Rust Remover since last week.  This is the stuff.  It works great.  Check it out: http://safestrustremover.com/


I only had a gallon so I put the crank, rotor side down, in a bucket, since last week.  Crappy picture but you get the idea.


Remember that here’s what it looked like before.


So I had the torch ready but decided to put the wrench on the rotor bolt and give it a test twist.  It came right off!   Then I put my special rotor removal tool (20mm hex head bolt) into the rotor and it came right off!!   Here’s what the rotor looks like after the soaking.  It’s not perfectly clean but that was with no brushing, no agitation, no nothing.  All I did was dry it off a little with a rag.


Some more good news, it’s the correct (for this VIN) 10mm bolt.


Here’s the 10mm hole.  The later sandcasts have a 12mm bolt.  Seems like that’s a pretty large increase.


So that went way too easy so I says to myself…(I won’t say it) why don’t I try to remove the spark advancer shaft.  I’ve been soaking it for weeks now.  I double nutted the threads and gave it try.  No go.  Out came the torch.  I heated on it for about 5 minutes.  She was smokin’.  Gave it another try and it came out!!  I’ve always had trouble with these probably because you’re trying to turn a 8mm thread with a 6mm shaft.


  So it was a good night.  Start to finish about ½ hour.  Now I’m really scared.  I’ve had kind of a good, bad, good, bad cycle.  I can’t wait to see what happens next.

[MCRider]

A stud extractor has always worked for me.  Like this but there are other better designs as well.
http://www.sears.com/shc/s/p_10153_12605_SPM213831557P?blockNo=3&blockType=G3&prdNo=3&i_cntr=1293550729652

[fasturd]

Hey Mark ... HURRY UP!   

Guys if it isn't obvious Mark's bikes are AWESOME. I showed my 400F along side his 750s this past spring at out local VJMC show, You just don't get tired of looking at stuff that is that nicely detailed.

Keep up the good work it is inspirational.

[fastbroshi]

Part of the charm/allure/mystique of sandcasts, besides being the first of that type of MC out of Japan, is the changes and evolution it went thru, over a short tun of 7400 bikes.  On the sandcast 750 there is between 50-75 parts (or more) that are unique to that group of bikes.That makes them much harder to restore correctly, and in turn drives up price of parts and finished bikes..
If I understand correctly, you are fixing your sidestand issues.. the other 69 frame you are using for reference? not cutting stand off, I hope?

You are correct.   I'm lucky to have the other early sandcast frame.  Welder says I won't be able to tell the difference when he's done with it.  And its partly because of what you said that there really is no other choice but to repair it and repair it right.  And FYI there are closer to 90 differences between early and late sandcasts.  Here's an interesting thread:
http://cb750sandcastonly.com/smf_forum/index.php?topic=217.0

Thanks for all the comments on the inner coating (or lack of).  It would be interesting to know for sure, but either way I won't be blasting the inside.

I think #20 and #88 on the page in your link may be describing the same thing

[markb]

Hey Mark ... HURRY UP!  

Guys if it isn't obvious Mark's bikes are AWESOME. I showed my 400F along side his 750s this past spring at out local VJMC show, You just don't get tired of looking at stuff that is that nicely detailed.

Keep up the good work it is inspirational.

Thanks for the nice complement!

I think #20 and #88 on the page in your link may be describing the same thing

Kind of but I think #20 is saying the thin-lipped alternator cover goes up to E2134 and #88 is saying that the smooth background on the Honda logo goes up to E342.  Interesting stuff.

[754]

Lucky you got the right crank, I sure wouldnt want to be needing one of them..

 I checked the 500-4 engine partsbook, when I found no differences. Mostly what I meant was they are mostly the same a few small differences. But on a sandcast, you could be missing dozens of parts, which not being correct can greatly reduce the value to someone knowing the difference, and they can be VERY hard to find..  whole different game..