Honda CB750 Sandcast

Expert Opinions Needed On Smooth Oil Filter Cover

markb · 8 · 3706

markb

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I’m trying to decide what I should do with my oil filter cover for #97.  It has a lot of pitting on top (front?) which appears to be mainly road blast but it’s actually has pitting all over it (is that typical?) that I’m assuming is original.  I thought I would sandpaper part of it away but how far should I go?  Some of it is pretty deep.


Also in this pic you can see what looks like remnants of paint.  Were some of these painted?  It could also be clear coat that’s been partially sanded.  You can see some of the pitting here too.  This cover didn’t come with the bike and who knows what’s happened to it.  My goal is to make it look as correct as possible for #97.  My thought is to sand the top until it matches the sides, polish it to a brushed finish and then clear coat it.  Any thoughts?
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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Mark, my experience, the tiny casting holes on the side and the sealing rim of your cover are visually apparent, resulting from the casting process.  

These casting holes are visually different from the peppering 'dents' caused by road blast on the front of your cover.  If not peppered to severely, perhaps you can see some of the tiny casting holes.... ?

My 232 cover had not as severe road blast peppering on the front; i chucked the cover in the lathe and gently cleaned the cover with fine steel wool.  Lessened the peppering without unacceptably altering original appearance.

I left my cover au naturel; no paint, no coating.

Seems not long ago, there was discussion specific to clear coating on these covers as well as paint....

My belief is the clear coat has degraded to look like paint.... ?  (Perhaps a trial of a tiny bit of paint remover on a small area of the coated?/painted? area to see if the coat/paint lifts off?)  I would hazard a guess if paint should easily lift off ?  If a clear coating, less resistant to paint remover... ?

I would suggest the original finish on your cover is clear coat.

As to Wayne's reference to Chris R's post on another thread, Chris certainly raises other keen observations.


vnz00

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Mark, I just posted photos of how I finished mine in the above thread. I posted the original finishes I had photos of and that owners had reported, and I worked to Chris' observations which was similar to what I started with.

I kept it all together in that thread as there was a lot of good info there for future reference.

Hope it helps,
Steven


markb

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Nuts, I thought I remembered that thread and I did look for it, just not the right category.  ::) Sorry for restarting a lot of the same questions but thanks for the great input.
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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In cleaning up my cover, what i am trying to say, there was enough patina to unacceptably 'match' the restoration quality of the rest of 232. 

I did not want to remove so much patina so as to make the cover look too good, because i wanted it evident the cover was not a reproduction.

Essentially, i removed enough of the patina and left enough of the patina to give the cover the appearance of what i thought would be as close to assembly line new appearing if possible; if that makes sense.  Trying to find a middle ground.


Prospect

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I agree with Steve.  If you take off too much you also run the risk of it looking like a shaved finned cover.  Just take a bit off to avoid a smooth finish.  I can't tell you about the patina or road rash of my smooth cover as it had been painted black sometime in the 80's. 
Vin 256/106


UK Pete

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mark , if i were restoring a sandcast i would follow the advise of partial restore so as to retain some patina, here is a nice example which i am sure you have all seen before , i would be aiming for a finish like that, i would go about it by turning it down a slight bit in lathe, then sand blast it in my small cabinet
I am sure you will get it right judging by your previous work
Pete