Honda CB750 Sandcast

DATE CODES

kp · 85 · 22589

Steve Swan

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here are pics of disc on 2157 and 232.  it is night time here, so my lighting is poor.

the "Q" code is on 232 disc.  the full code is Q 42 B.  the "Q" looks like an "O" but it clearly has a hash mark in the 5 o'clock position of what looks like an "O"

the "N" code is on 2157 disc.  the full code is N - 1651.  you will note there appears an "x" under each "1"

my apologies for not more pics.  232 is a bit "buried."  when i have a bit more time, in near future, i'll push 2157 into sunlight and look for more codes.

i should have documented all the stamped codes on both bikes when i had them apart, but, i did not.......... my bad :-X

so !  what do we speculate the date stamped on the disc of 2157 ?

and what date do we speculate stamped on disc of 232 ?

would be nice to hear from Sam Roberts and Chris Rushton.  for that matter Keith Byers and Marty Kitner where ever they are hiding out !

another part with code stampings is the gas tank.


Steve Swan

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i'll photo what i can off of 2157 and 232.  

232's disc is stamped "Q 42 B"  i have no reason to doubt the disc is original to 232 coming off the assembly line, the 232 chassis was very complete and unmolested when i took ownership.

Thanks Uli, if you have more, please keep the pics coming.
This is the item that has always had me intrigued. The Q and the B is of particular interest The 42 could be February 1969 maybe

if we use the Showan calendar dating system, the "4" certainly could represent a 9 and the 2 the 2nd month.

fwiw, "Q" is the 17th letter of the English alphabet.  "O" is the 15th letter.  "N" is the 14th letter.

in the not too distant future, 2157 will need a rear tire change, i can then look at the stamp on the brake backing plate.

for your entertainment, here are pics of 232 and 2157 when i took delivery of each bike.



Steve Swan

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i cannot remember........  this is a bit off subject, did we ever do a month to month analysis list of where we believe vin breaks occurred for approximately each month ?

looking at the vin directory, we can sort of make an ASSUMPTION of vin numbers manufactured each month, beginning March through September....

crank case casting dates were one of the very first date codes we started talking about well over a decade ago........

E342 is the 1st case we have recorded with a code 4/6, frame 302.

E338 through E407 we have 3 date codes, 4/5, 6 & 7, frames 302, 374, 388.

E602 - E748 we have 2 date codes, both 4/15, frames 530 & 576.

onward from E748 through 7414, we have a few more date codes, not a whole lot more considering the approximately 500 vins we have on record.  SAD, REALLY, in my not so humble opinion.

i guess the reason i am bringing this up, one could expect to see similar date stampings on the various chassis parts of these Fvin/Evin pairs.  However, crank case date codes ONLY SOMEWHAT correlate to  the manufacture date, that is, the date the Evin was paired with a Fvin on the assembly line.  we DO know some of the crank case date codes are quite disparate from significantly higher numbered Fvins, so any assumptions we would make about what distinctions of any certain part found on any particular vin is a guess at best.

has anyone found what one could assume could be date code stampings on frames ?  (i can't remember if we discussed this or found any...)

Again, thank you Uli, for taking pics of your stamped codes and posting them  ;D ;D ;D ;D



kp

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One could conclude that the numbers 1 have been crossed out with an X leaving 65
Yabba Dabba KP


kp

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I thought Chris Noel found frame date codes
Yabba Dabba KP



Steve Swan

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Steve Swan

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it's not a chassis part, but.....  here tis.....

a "24" ink stamped on the early "criss-cross" cam cover.

April 2 ?  or February 4 ?  i would say the date stamp is April 2.

Is it a valid assumption the factory was manufacturing production parts BEFORE the #1 Fvin rolled off the assembly line ?


kp

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Code on VIN28 disc
Yabba Dabba KP


kp

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I'm starting to think the numbers are month day codes given the sequence emerging.
I still have no clue about the alpha stampings
Yabba Dabba KP


Steve Swan

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i just checked gas tank on 2157, stamped "4 . 6 4"  so.... using Showan 1969 year.  6th day of 4th month?  or 4th day of 6th month? 

i cannot visualize any stamped marks on the 19 liter of 232.....


Steve Swan

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Code on VIN28 disc

so.... KP, your Fvin 28 disc is "3-3" = March 3rd ?  

my Fvin 232 is "42" = April 2nd ?

mine has a Q and a B with no dash in between the 4 and the 2.

yours has a R and a R with a dash in between the 3 and the 3.

i find it interesting that you have a dash between numbers and i do not.  imho, that is an inconsistency between stampings and within stamping practice.  these two inconsistencies lead me to believe 2 different people stamped these 2 different discs.  

based on the findings of the preceding stamps. i would suggest the numerals are dates.  i would suggest the alphabet letters identify the person who inspected and passed off the discs so they could be used on the assembly line.  those discs HAD to be inspected for trueness, after being precision ground.

and Fvin 2157 disc date is June 5.....  and my gas tank is June 4.  and, Uli's numbers are all within a close date range.   perhaps we are finding some consistency.......???


Steve Swan

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One could conclude that the numbers 1 have been crossed out with an X leaving 65

yes, that makes sense, as we have seen this "x stamping practice" on a couple Evins a few years ago.