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

All flathead topics
Speeding Big Twin
Posts: 1067
Joined: Wed Dec 31, 2008 2:29 am
Bikes: H-D
Location: Western Australia
Has thanked: 19 times
Been thanked: 132 times

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

#31

Post by Speeding Big Twin »

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 1661 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 1661 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
Service Bulletin 439 (page 1).jpg (235.11 KiB) Viewed 1661 times
Service Bulletin 439 (page 2).jpg
Service Bulletin 439 (page 2).jpg (140.88 KiB) Viewed 1661 times
Service Bulletin 439 (page 3).jpg
Service Bulletin 439 (page 3).jpg (223.05 KiB) Viewed 1661 times



Speeding Big Twin
Posts: 1067
Joined: Wed Dec 31, 2008 2:29 am
Bikes: H-D
Location: Western Australia
Has thanked: 19 times
Been thanked: 132 times

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

#32

Post by Speeding Big Twin »

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 721 times

Trans case (underneath).jpg
Trans case (underneath).jpg (70.07 KiB) Viewed 721 times

Trans case (front).jpg
Trans case (front).jpg (70.98 KiB) Viewed 721 times

RooDog
Site sponsor
Site sponsor
Posts: 1948
Joined: Tue Oct 31, 2017 1:00 pm
Bikes: 1950 Panhead, Resto-Mod
1968 90", 5 Speed Shovelhead,
1984 Custom Built Evo 100" Bagger
Location: Knoxville, Tennessee
Has thanked: 899 times
Been thanked: 767 times

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

#33

Post by RooDog »

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....

RUBONE
Moderator
Posts: 6250
Joined: Sat Nov 15, 2008 4:09 am
Bikes: Multiple H-D, Ducati, BMW, Triumph, BSA,...
Has thanked: 139 times
Been thanked: 1310 times

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

#34

Post by RUBONE »

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.

Speeding Big Twin
Posts: 1067
Joined: Wed Dec 31, 2008 2:29 am
Bikes: H-D
Location: Western Australia
Has thanked: 19 times
Been thanked: 132 times

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

#35

Post by Speeding Big Twin »

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

Post Reply

Return to “Flathead and Servi-Car”