#Harley Transmission Serial Numbers serial numbers
#Harley Transmission Serial Numbers code

Clearance at first may have been achieved by the factory machining bosses that were cast round but at some point the bosses were cast flat. This example was cast in June 1945 (F 5).Д«ut as of 1947 models those two bosses were flat to provide clearance for the (hand) gear shifter lever which was changed from pointing up to pointing down.

Two bosses at upper left front: in the next picture the two rounded bosses normally help indicate a 1946 or earlier model case.

#Harley Transmission Serial Numbers code

There are other things too that can assist with ID of a 121 35 case cast prior to date code introduction so if your 121 35 case has no date code then please let me know and IвЂ™ll try to help identify it. In that instance, the case probably had a bronze insert originally and then it had been replaced later on with a steel insert.ДЄlso, there are reports that the mounting bolt underneath on the R-H side debuted on some early-37 models as opposed to mid/later-37s. NB: recently on another site I ran across a D 9 trans with a steel insert but it wasnвЂ™t a 1949 case because three other features definitely indicated April 39 as opposed to April 49. The change from bronze to steel apparently occurred around late-43вЂ“early-44. Also fitted with a bronze insert is this July 41 (G 1) case.Д«ut the May 44 (E 4) case below has a steel insert. Also itвЂ™s possible for anyone else to drill a boss at any stage so always check for other ID.Д«ronze insert or steel insert? As seen above, the Sept 38 case and May 39 case have a bronze insert underneath for the mounting bolt on the R-H side. However, if such a case was a replacement to be used for a 55 or earlier machine then the case boss may have been machined as original. The vent nipple remained in the case boss through 1955 models but as of 1956 models the boss was originally left unmachined and H-D changed to vent screw #34720-56 placed in the lid. Was it done at the factory? By a dealer? By someone else?ДЄlso with no vent boss but a machined hole is this April 1939 case.Д«ut as early as May 39 (E 9) there was a cast-in boss for a vent nipple.ДЄnd because the boss appeared as early as May 39 casting, it may be possible this type of case was first used for some late-39 model machines. However, some cases with no vent boss have a machined hole as per the next example cast December 1938. In those instances, venting was usually handled by a nipple in the starter cover. Vent in the case or not? For the first few years the 121 35 case had no boss for a vent-for example, this one cast in September 1938. For 1964 Panheads, some had a 121 35 case while others had a case with casting number 34703 64 and IвЂ™ll come back to that later. The same casting number also appears for Knuckleheads 36вЂ“47, BT Flatheads 37вЂ“48 and Panheads 48вЂ“63.

#Harley Transmission Serial Numbers serial numbers

That casting number may have first appeared with Knuckleheads that had 1935 serial numbers (at least four were built as prototypes for 1936 models). On occasion it has worn down but the two examples below are still fairly good. As you see above, I have no examples between 3 3 and 1 58.Д¬odes in my list from the beginning through 2 63 are on cases with casting number 121 35. I cannot explain why 3 3 was used for so long. Notice 1959 codes sometimes had 59 indicating the year but sometimes only 9 and I have seen the same thing on some other 1959 castings such as crankcases and heads.Дate code 3 3 at first may have indicated casting in March 1953 but it remained for some time and has also been found on trans cases of bikes as late as 1956вЂ“57 models that are unaltered from original. Regarding the letters I and M, see below for further mention. Notice J 6 (spaced) and J6 (unspaced) were apparently both used for October 1946. Notice the period August 1948вЂ“March 1949 where there is no space.

Notice most codes have a space between month and year but some do not. Listed below are date codes I know of so far on BT trans cases cast April 38вЂ“December 63:ДЄ 9, B 9, C 9, D 9, E 9, F 9, H 9, I 9, J 9, K 9Д 6, E 6, G 6, H 6, I 6, J 6, J6, L 6 (See below re two codes with J)ДЄ 7, C 7, D 7, E 7, G 7, H 7, J 7, K 7, L 7ДЄ 8, B 8, C 8, E 8, F 8, G 8, H8, J8, K8, L8, M8 Numbers-only codes appeared as early as January 1950. The letter-number format seems to have then continued through the 1940s. On H-D BT trans cases the earliest letter-number date code I am aware of is from April 1938.