Restoration of Sandcast #97

[Steve Swan]

I can't remember, did 97 have updated drive cushions ?  If so, the punchmarks could be from the update ?

[cb7504]

Mark: Nice job of blending on the rear flange it looks real good. I think i'll go the same route on my rear flange. Marty K.

[cb7504]

Steve: It looks like the drive cushions were updated at one time (see page 23 of this thread). Marty K.   

[markb]

Mark: I would not remove the three punch marks as they are part of the history of the bike indicating service bulletins have been complied with on this particular vin. Marty K.   

Good point, I agree.

Steve: It looks like the drive cushions were updated at one time (see page 23 of this thread). Marty K.   

Weren't the cushions updated to the non-symetrical version (different size)?

[cb7504]

From what i understand the first version of drive cushions were large symmetrical with NO holes, second version large symmetrical with holes, third version four thin and four large drive cushions. I would think yours were changed from the large symmetrical NO HOLE version to the large symmetrical holed version as shown on this thread on page 23. Marty K.   

[markb]

Mark: Nice job of blending on the rear flange it looks real good. I think i'll go the same route on my rear flange. Marty K.

It takes some time but I think you'll be pleased with the results.

From what i understand the first version of drive cushions were large symmetrical with NO holes, second version large symmetrical with holes, third version four thin and four large drive cushions. I would think yours were changed from the large symmetrical NO HOLE version to the large symmetrical holed version as shown on this thread on page 23. Marty K.    

I agree with that too.  It looks like the second version came with Service Bulletin #15 dated March 16, 1970 and the third version came with SB #32 dated August 13, 1971.

[Steve Swan]

Page 6 of SB #15, reads - "Identify the installation of the rear hub damper rubbers by making three center-punch marks on the drive flange hub just outboard of the final driven sprocket at the rear wheel hub (see Fig. 4)."

Not to steal the topic, but SB #15 and it's revison dated 1/31/75 both discuss, "Some early CB-750 units used large coils...."  The SB goes on to discuss the specifics of filing a small notch in the frame cross piece to clear the larger junction box of the replacement 1-4 thr.cable assembly.

Mark, does #97 have coils different from your later vins ?  Has there been a notch filed in the frame cross piece ?  (Drawing on page 8 of SB #15 show where the notch is to be filed.)

I seem to recall looking for this modification on 232 which did not have a notch filed in the cross piece and the coils appeared same as coils i've seen on all other units.  (Coils/brackets appeared having not ever been moved until my ownership.)  232 came with a K4 engine which had earlier K1 type carbs installed.  With the boxes of 'sandcast' parts accompanying 232, came the early long choke lever carbs replete with 3 of 4 of the #28 caps/assemblies.  One #28 assembly was missing.

[markb]

Mark, does #97 have coils different from your later vins ?  Has there been a notch filed in the frame cross piece ?  (Drawing on page 8 of SB #15 show where the notch is to be filed.)

I am familiar with that modification.  I will have to check the coils and see if my frame has the notch.  I will report back.
Mark

[Steve Swan]

It would be nice to have side by side pictures of early and later coils.  Another difference to go into the "Distinctions" list.

[markb]

On to the oil filter cover.  There is a lot of road blast on it.  And there are pits and imperfections all over it which I’ve learned are typical on the early smooth covers.  My plan is to remove enough of the blast to make it look about the same all over.


I carefully chucked it in the lathe and went to work with sandpaper.  I think it turned out pretty good.


There are still plenty of imperfections.  It’s hard to resist removing them.  Next a brushed polish finish and then clear coat.

[Wayne]

Looks great Mark! I wouldn't remove a spec more!

[cb7504]

Mark the oil filter cover has just the right look, be extra careful when you tighten the center bolt when you reinstall it on the engine, the cover cracks under pressure fairly easily. Marty K.   

[UK Pete]

Great work, i would say you got that just right mark

[kp]

An Ozzie expression is "spiffo" which translated into Yankee speak is Man that is Ohhhhhh so good

[markb]

While I was at it I figured I might as well clean up my oil filter cover with the fins removed.  Can you tell which one is the real thing?


Of course you can tell when you look inside.  The fake is on the left.  I'll probably use it to test run the engine to avoid risking cracking the real one and put the real one later.


And you can also tell by looking closely at the surface.  The real thing won’t be smooth.  By the way, I'm not done polishing yet.

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