LEFT & RIGHT SWITCH DATE CODES

[kp]

Anyone who plays around with early Z1 Kawasaki bikes knows how important date codes are to an original unrestored or restored bike. Seems our group haven't been too specific with date codes although there has been some discussion on the topic. I have been doing some inventory of my Z1 parts collection and decided to have a look at a group of Honda switches I have. I noted that these original Honda switches also have a date code stamped on each switch end. I doubt I'm the first to note this fact, nevertheless I can't recall/remember any previous discussion on the subject. Given I'm "anal" about this sort of stuff I thought I would share what I have.
The switches photographed are of Left Side (4 of) and Right Side (1 of). Three of the Left switches have the stamped "MADE IN JAPAN" on the under side and one Left switch has the raised embossed "MADE IN JAPAN" The Right switch is off a K0 but these don't have any made in Japan markings but DO have a date code.
These stamped codes use the Emperor Showa system for the year followed by a normal calendar month code, so we have 3 = 68, 4 = 69, 5 = 70 and 6 = 71. Therefore we have 2 from 1968, 2 from 1969  and 1 from 71. All the Left switches stamped "MADE IN JAPAN" are either 1968 or 1969 coded. The Left switch with the raised embossed "MADE IN JAPAN" is from 1971 The Right switch is from 1969
To summarise
LH Switch 1 stamped 3.6 = June 1968
LH Switch 2 stamped 3.11 = November 1968
LH Switch 3 stamped 4.10 = October 1969
LH Switch 4 stamped 6.05 = May 1971
RH Switch 1 stamped 4.12 = December 1969
Hope this is of interest to the group and others contribution would be welcomed
 

[Sgt.Pinback]

Hi Kerry,

nice find. I saw them on my Z1 but didn't knew Honda has dates on the switches too.

Are you sure that the fist figure gives the year and not the month?

If so, we have yet another mystery:

Ma # 1983 sandcast gives

left hand switch  5 7 So that would be Juli 1970 ?!
right hand switch  4 6  that would be June 1969

both would too far away from the rest of the bike (all Mai 1969)

So I'd go with Mai, 7 and April, 6

Would be great to see more data from sandcast.

[kp]

Uli, I think you will find your bike is a June/July build and the RH switch is correct date code. I note it is somewhat faded whereas the LH is much less faded. Can you supply a photograph of the underside of your LH switch.
I am very sure (and indeed convinced) that the first number is the year code based on Showa. I have many more switches with codes and these match the Showa year system.

[Sgt.Pinback]

Kerry, all data on my bike say Mai or earlier.

Here are the pics. Upper left / right switch are mostly the same way faded.

The underside of the left switch is less faded than the right underside.

However, the data code is on both sides on the upper part.

[kp]

Uli
I'm not so sure that is the original LH switch to this bike. Maybe it is or maybe it isn't. I believe the bottom half is of later manufacture
As for parts being May this would be correct for June or July production. Given engine cases were cast in late May, it would not have been possible to be assemble cases into an engine and then put into bike by end of May. Steve is better placed to talk on production start up but I am sure that your bike is a June or July production.