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39 E Transmission Gearing

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  • 39 E Transmission Gearing

    I am new to the forum and I'm looking for any input I can get. I am building a 1939 "E" medium compression knucklehead. Although the standard gear setup for an EL in 39 was 12N34, I don't know if it would be the same for the E model. I have been told that the E model was used primarily as a police and sidecar bike. So I thought an E may run a 123R pattern. I am looking to get any information I can get how I should set up my tranny.

    Thanks for any help

    Eric
    Last edited by knuckjunky; 11-14-2009, 10:15 PM.
    Eric Hitzel
    AMCA 14954

  • #2
    Originally posted by knuckjunky View Post
    I am new to the forum and I'm looking for any input I can get. I am building a 1939 "E" medium compression knucklehead. Although the standard gear setup for an EL in 39 was 12N34, I don't know if it would be the same for the E model. I have been told that the E model was used primarily as a police and sidecar bike. So I thought an E may run a 123R pattern. I am looking to get any information I can get how I should set up my tranny.

    Thanks for any help

    Eric
    '39 was a year of change. Starting out with the 1 2 N 3 4 but ended with 1 N 2 3 4. The 1 2 3 R would be on a sidecar bike. Not all sidecar units had reverse.
    Be sure to visit;
    http://www.vintageamericanmotorcycles.com/main.php
    Be sure to register at the site so you can see large images.
    Also be sure to visit http://www.caimag.com/forum/

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    • #3
      Chris I restored 39EL50xx for the nephew of the original owner 15 years ago and it still had the 12n34 tranny. When did the change occur.... and why in God's name did they ever dream up that mess in the first place.

      Jerry

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      • #4
        Actually it is R1N23! Lots of early police units were 3 speed only.
        Robbie
        Robbie Knight Amca #2736

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        • #5
          Thanks guys. My motor is 39E30##. I am told that the medium compression E motors came with both 12N34 and in three speed depending on what you ordered. I have both gear sets and I just want to make sure which oneboth is really correct before I build it.

          Did the E models come in both gear sets? If so, do you guys know which were more common. I'm not going to build a police bike so I want to know how a civilian E model would most likely have been geared.

          Thanks again,

          Eric
          Eric Hitzel
          AMCA 14954

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          • #6
            i've been told the case was machined differently inside between the two but i couldn't tell you how or where----maybe carl olsen could help with this??

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            • #7
              All the Big Twins, both OHV and SV, came standard with the 4 speed. The 3 speed and 3 & reverse were options and had to be stated on the initial order. So unless you know your bike came with a 3 Speed and can verify it, the most correct way is the 4 speed, 12N34.
              Robbie
              Robbie Knight Amca #2736

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              • #8
                Being on the subject of 1939s with a one year only transmission
                having a sliding gear, for 1st and 2nd.
                My question is? could you take a trans. from another year, and rework
                the shift drum. and move the detent, so that neutral is between 2nd and 3rd?
                I have looked at regular 4 speed shift drums, and the detent spacing between gears are
                the same, with neutral, mid point between 1st and 2nd. possibly the slot in the drum for
                the shifter fork, may need finessing? I know that this is would have to be very precise
                to work and be safe Any thoughts Regards Lee

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                • #9
                  LJH It is possible and I have done it. After restoring a 39EL and a 39UL with that miserable shifting 1939 tranny, I decided something else was in order. It took a bunch of work on the shiftdrum and I used 3 up to get one finished product. I never rode the bike it went into but the guy says he likes it and so far no problems. I just did it this past spring.

                  Jerry

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                  • #10
                    Originally posted by LJH View Post
                    Being on the subject of 1939s with a one year only transmission
                    having a sliding gear, for 1st and 2nd.
                    My question is? could you take a trans. from another year, and rework
                    the shift drum. and move the detent, so that neutral is between 2nd and 3rd?
                    I have looked at regular 4 speed shift drums, and the detent spacing between gears are
                    the same, with neutral, mid point between 1st and 2nd. possibly the slot in the drum for
                    the shifter fork, may need finessing? I know that this is would have to be very precise
                    to work and be safe Any thoughts Regards Lee
                    I believe the shift drum for the 39 four speed is the same as the 39 to mid 70's 3 speed reverse drum, so there should be lots around. You got me curious now and I have one of those drums, and I'm in the middle of doing up a hand shift tranny for my shovel so I'll look into that.

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                    • #11
                      Thanks Jerry
                      I have mentioned this to a couple of other guys, and I got the "blank" stare
                      yes that 39 trans is a pain. and hard to find
                      I knew it could work, You go through the neutral position, everytime you shift.
                      just relocate it, between 2nd and 3rd.
                      Lee

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