Honda CB750 Sandcast

Reproduction early tach and speedo cables

markb · 40 · 12090

Wayne

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I measured the tach cable nut from 576. The taper is about .5 mm. For you guys still in the stone age that's about .0196". ;) Is that what you are seeing Mark?

What I would like to know is...why does everyone else seem to have a hole on the gauge end yet the tach cable from 576 does not?? Were there different cables made, some no hole, hole added later...or did mine simply miss the process? Another unanswered question in the world of the beloved sandcast. :)
« Last Edit: December 21, 2012, 12:32:30 pm by Wayne »
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markb

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I measured the tach cable nut from 576. The taper is about .5 mm. For you guys still in the stone age that's about .0196". ;) Is that what you are seeing Mark?
Yes.  You really have to look close to see it.

What I would like to know is...why does everyone else seem to have a hole on the gauge end yet the tach cable from 576 does not?? Were there different cables made, some no hole, hole added later...or did mine simply miss the process? Another unanswered question in the world of the beloved sandcast. :)

I'm feeling a little stupid here since in a earlier post I indicated that all my tach cables had the hole.  I just checked and the tach cable from #97 does not have a hole.   :o ???  So you're not crazy Wayne.  I see that Steve's #232 tach cable had a hole.  Maybe we can assume from this that some of the early tach cables did not have holes and obviously some of them did.  I'm guessing that getting a fitting for the tach cable without the hole will be a problem and that using one with a hole will be correct enough.  That's my story and I'm sticking to it.  
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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Mark, "stupid" is being a tad harsh.  ;) Details are so easily overlooked on these bikes. Go easy on yourself!   ;) Being that my early tach cable is a "no hole" and in excellent shape other than some paint on it I'm going to try and restore the zinc on the fittings and I assume nut? Now, I wonder if my original speedo cable was a "no hole"? Does this fall into the category of another "distinction"? Looks like they may be random unless we can prove otherwise with a vin breakpoint. Steve's 232 has kind of thrown a wrench into that theory, unless the cable was replaced for whatever reason when short nut cables were available through Honda parts dept.
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markb

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I checked the cables on the gauges and they fit great.  I just wanted to make sure the threads in the nuts matched.  For anyone who wants to know the thread is M12 x 1.0 (different than the M12 x 1.25 threads elsewhere on the bike).

Riccardo (and those interested in getting a set of these) I talked to Joe and they do not document the custom cables.  You will have to send your cables and ask for cables to match as close as possible to yours (and they will be different as indicated in my previously posted pics).  If you only have cables with standard length nuts you will have to request using the shorter nut.  Joe said there is only one so that shouldn't be a problem.

I'm still planning on trying to manufacture some correct nuts.  If I supply nuts and my old cables Joe said he could make them up.  If you're interested in using correct nuts and are willing to wait that is another option.  However, at this point I'm not sure how soon that will happen or how much it will cost.  I have to get one off the old cable and measure it up and check around for manufacturing.  Then I would have to decide if I would just supply nuts and let everyone else pursue their own option or get a batch of cables made.
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?)


hondasan

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Wayne,
I believe you will find that the nut itself is not zinc plated, actually being made from some aluminum alloy material, much the same as the "sandcast" drive body on the back of the clocks theirselves. The nuts therefore tend to clean up pretty well, just the zinc fitting on the end of the cable itself to deal with.

Cheers - Chris R.
Chris R.
302/338


markb

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Good observation!  I just put a magnet on my originals and they are definately not steel.  A file shows that they are too soft to be stainless.  The MP nuts are not steel either.  It sure is good to have more than one set of eyes looking at these details.  :)
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?)


hondasan

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Just to add another angle to this subject...
#302 came to me with its original short nut tacho cable, but later long nut replacement speedo cable. Both cables were in good condition, so the tacho one was simply cleaned and re-used. the speedo cable nut was shortened (still on the cable) and then re-used. Pictures below for comparison. Obviously the modified speedo cable does not have the slight taper, but good enough for me. To shorten the speedo cable nut, a small hose clip was fastened around it to provide an edge to cut surplus material from the nut lower edge, then moved little to provide an edge to file / polish away the "splines" to create a nut close in appearance to the tacho cable one. Fortunately there was enough surplus material on the nut to enable shorteneing and still be able to attach to the speedo drive. It was easier to do than I feared, just care an patience - oh, and I did prcatice on an old scrap cable first!

Cheers - Chris R
Chris R.
302/338


markb

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Chris,
That's another good option.  Especially knowing now that they're not made of steel.
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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Yes, agreed.  Chris and i batted this one around on personal email. 

Based on Chris's experience, I also used my lathe to turn down a long nut to short nut length. 

I used a piece of PVC tubing to keep the cable from flailing about in the lathe.


Riccardo

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Just to add another angle to this subject...
#302 came to me with its original short nut tacho cable, but later long nut replacement speedo cable. Both cables were in good condition, so the tacho one was simply cleaned and re-used. the speedo cable nut was shortened (still on the cable) and then re-used. Pictures below for comparison. Obviously the modified speedo cable does not have the slight taper, but good enough for me. To shorten the speedo cable nut, a small hose clip was fastened around it to provide an edge to cut surplus material from the nut lower edge, then moved little to provide an edge to file / polish away the "splines" to create a nut close in appearance to the tacho cable one. Fortunately there was enough surplus material on the nut to enable shorteneing and still be able to attach to the speedo drive. It was easier to do than I feared, just care an patience - oh, and I did prcatice on an old scrap cable first!

Cheers - Chris R

GREAT IDEA!
I'll try.
Thanks.
Riccardo
Riccardo
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