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Author Topic: Cylinder Head Code???  (Read 1162 times)

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Offline EMac

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Cylinder Head Code???
« on: March 12, 2017, 01:43:22 PM »
I have what I believe to be 2 '72 engines.  When trying to pick the best to use for a rebuild I noticed only one had these codes stamped in the bottom of the cylinder head.  I'm sure many of you know exactly what they mean and why one has it and another does not???

Thanks.
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Offline evinrude7

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Re: Cylinder Head Code???
« Reply #1 on: March 12, 2017, 03:59:50 PM »
emac, i'm a newbie here.  i found this page.  maybe you know about it already maybe you don't.  i pulled up the page and then searched cylinder head within the page and there is some talk about casting marks.  i didn't delve thru the details.  i don't know if it's any help.  good luck man. 

http://honda750expert.com/
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Offline Don R

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Re: Cylinder Head Code???
« Reply #2 on: March 13, 2017, 08:52:06 AM »
 The one with the codes I assume to be the newer of the two, the number indicates the year but it's the year since the emperors birth or something like that.
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Offline MikeSimon

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Re: Cylinder Head Code???
« Reply #3 on: March 13, 2017, 01:10:51 PM »
Quote from: Don R on March 13, 2017, 08:52:06 AM
The one with the codes I assume to be the newer of the two, the number indicates the year but it's the year since the emperors birth or something like that.

Not sure in this case. From the CBX data I know that 53 is 1978. This would mean 24 is 1969. Couldn't be a 72 head then...
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Offline 754

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Re: Cylinder Head Code???
« Reply #4 on: March 13, 2017, 01:46:50 PM »
 Those are barrels or cylinders, after 40 years all i know is they are casting  or batch numbers , I cant tell age from them. Btw they are cast in not stamped. show a pic of the head from above, sometimes topends get switched...heads changed distinctively in early 73.
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Offline Don R

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Re: Cylinder Head Code???
« Reply #5 on: March 13, 2017, 04:17:05 PM »
 The early castings had the dates on a small raised pad indicating month and year. The later had the numbers and letters in the hex recesses.
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No matter how many times you paint over a shadow, it's still there.
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Offline EMac

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Re: Cylinder Head Code???
« Reply #6 on: March 13, 2017, 07:33:16 PM »
The cylinders with the hex recesses come from an engine I know has been gone through before.  Likely a newer cylinder someone put on.  The cylinder heads on both my engines are consistent with pre 73 heads.  Just an interesting observation as I'm trying to prep reassembling the best motor possible. 

I started this whole process with the goal of learning more about how motorcycles work...rather than how to just look cool sitting on one.  So far, so good.
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'72 Honda CB750

Offline ekpent

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Re: Cylinder Head Code???
« Reply #7 on: March 14, 2017, 04:54:01 AM »
 One way to date a cylinder a little better is the style of rubber o-ring gaskets on the top side of the deck.
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