Date codes and other info for some, not all, BT trans cases

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Speeding Big Twin
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Re: Date codes and other info for some, not all, BT trans cases

#31

Post by Speeding Big Twin » Mon Mar 05, 2018 10:15 am

Below is another example to add to the list. Date code 5 61 indicating casting in May 1961.

May 1961.jpg
May 1961.jpg (119.9 KiB) Viewed 1377 times
Earlier in the thread I mentioned vent screw #34720-56 was placed in the trans lid as of 1956 models. This is confirmed by Shop Dope 372 dated February 6, 1956.

Shop Dope 372.jpg
Shop Dope 372.jpg (143.63 KiB) Viewed 1377 times
Another interesting document is Service Bulletin 439 issued March 29, 1961, addressing a change to the Duo-Glide speedo drive. Notice the last paragraph on page 1 says the letter C will be found stamped in a certain position on some transmission cases. I don’t recall noticing a C yet in that location so if anyone has an example then please let me know.
Eric

Service Bulletin 439 (page 1).jpg
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Service Bulletin 439 (page 2).jpg
Service Bulletin 439 (page 2).jpg (140.88 KiB) Viewed 1377 times
Service Bulletin 439 (page 3).jpg
Service Bulletin 439 (page 3).jpg (223.05 KiB) Viewed 1377 times



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Re: Date codes and other info for some, not all, BT trans cases

#32

Post by Speeding Big Twin » Fri Oct 18, 2019 10:53 am

In June 2016 I said I'd never seen a date code on a 34703 65 trans case and that was true. But here is one (1-77) indicating casting in Jan 77.
Eric

Trans case (1-77).jpg
Trans case (1-77).jpg (51.59 KiB) Viewed 437 times

Trans case (underneath).jpg
Trans case (underneath).jpg (70.07 KiB) Viewed 437 times

Trans case (front).jpg
Trans case (front).jpg (70.98 KiB) Viewed 437 times

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Re: Date codes and other info for some, not all, BT trans cases

#33

Post by RooDog » Fri Oct 18, 2019 1:59 pm

Speeding Big Twin wrote:
Fri Oct 18, 2019 10:53 am
In June 2016 I said I'd never seen a date code on a 34703 65 trans case and that was true. But here is one (1-77) indicating casting in Jan 77.
Eric

Trans case (front).jpg
Eric,
What is the significance of the number you have redacted?
....RooDog....

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Re: Date codes and other info for some, not all, BT trans cases

#34

Post by RUBONE » Fri Oct 18, 2019 2:35 pm

RooDog wrote:
Fri Oct 18, 2019 1:59 pm
Speeding Big Twin wrote:
Fri Oct 18, 2019 10:53 am
In June 2016 I said I'd never seen a date code on a 34703 65 trans case and that was true. But here is one (1-77) indicating casting in Jan 77.
Eric

Trans case (front).jpg
Eric,
What is the significance of the number you have redacted?
....RooDog....
It is a unique ID number and is traceable back to the bike it came from by H-D often referred to as an anti theft number. It is the same format as the ones used on forks and frames.

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Re: Date codes and other info for some, not all, BT trans cases

#35

Post by Speeding Big Twin » Sat Oct 19, 2019 11:22 am

RooDog wrote:
Fri Oct 18, 2019 1:59 pm
Speeding Big Twin wrote:
Fri Oct 18, 2019 10:53 am
In June 2016 I said I'd never seen a date code on a 34703 65 trans case and that was true. But here is one (1-77) indicating casting in Jan 77.
Eric

Trans case (front).jpg
Eric,
What is the significance of the number you have redacted?
....RooDog....

On the front of the trans is an additional original component identifying number, aka security code, aka anti-theft number, aka supplemental number. Some believe the practice began in 1963 while at least one publication said 1961. Several others say the additional ID began with 1962 models and I agree.

In the beginning, when used for Big Twins, it was stamped on the trans, frame and lower triple clamp and it consisted of one letter followed by either three or four numeric characters. Along with the SN and BNs, the additional ID on each bike was recorded at the factory and I imagine it may have been useful in warranty and/or recall situations. It was also of assistance to police when investigating bikes and/or parts thereof.

In the past, some forum members had all the additional ID on their bikes confirmed as original by H-D but as of more recent times it is unclear how much info the factory still has.
Eric

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