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Thread: 5 speed transmission

  1. #1
    Registered User R100RTurbo's Avatar
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    5 speed transmission

    The transmission is s/n ZSA079719:
    a) regarding the output shaft circlip usage, anyway to know its in there other than a disassembly? (no issues or symptoms and clean magnet plus yoke rotates smoothly with no sounds)
    b) what is a reasonable input shaft "free play", with regard the torsion spring and ramps built into the front gear and such? (again no symptoms/ problems but roughly 80 degrees rotation noted to a feel of contact).
    Technical detail not immediately found in the better known sites and expert documents, so help appreciated.
    LW

  2. #2
    Administrator 20774's Avatar
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    If I understand Snowbum's site, the "79719" seems to fall in the 1984 timeframe. He has yet to find any '84 transmissions that are missing a circlip.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    . AntonLargiader's Avatar
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    There have been plenty of '84s without the circlip. You can't tell without disassembly.

    The rotational play you mention isn't in the input shaft but rather in the gear dogs. If you have a broken input shaft spring, though, you will get more of it; I will try to remember to check a few of them this coming week to see what is normal. Normally the shaft has no play under hand pressure.
    Anton Largiader 72724
    largiader.com bmwra.org

  4. #4
    Administrator 20774's Avatar
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    Anton -

    Have you provided the specfics of 84s w/o ciclips to Snowbum? As you know, he has asked the Airhead community to provide these details and he will gladly publish on his website. It sure would be good to expand his information w/ yours.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  5. #5
    Registered User R100RTurbo's Avatar
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    Hand Pressure

    Quote Originally Posted by AntonLargiader View Post
    There have been plenty of '84s without the circlip. You can't tell without disassembly.

    The rotational play you mention isn't in the input shaft but rather in the gear dogs. If you have a broken input shaft spring, though, you will get more of it; I will try to remember to check a few of them this coming week to see what is normal. Normally the shaft has no play under hand pressure.
    Thanks for the help Anton and Kurt.
    The play that exists between the "dog ramps" is very free and without having the component apart to witness, certainly lends the impression of perhaps a short torsional spring. (do they loose tension?)
    It is pretty much close to a quarter turn between obvious mechanical contact between those surfaces inside.
    There is no previous or current metal on the magnet but pending your advice on comparative units, plus the random potential of no circlip residing within, I will be adding one more job to this winters list. I noted Bob's request for feedback (@ Snowbum) on these years of bike trannies in regards to the circlip, and judging by what is shaping up, will be able to offer one more "yea/ nay" to his records.
    LW

  6. #6
    . AntonLargiader's Avatar
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    Quote Originally Posted by 20774 View Post
    Have you provided the specfics of 84s w/o ciclips to Snowbum?
    Yes. I've only found one or two, but I've talked to others who have also found them. There aren't many, and they have circlip grooves but no circlip. Come to think of it, I might have just had another one in the last few weeks.

    Anyway, I have a hard enough time keeping my own website up to date without worrying about someone else's!
    Anton Largiader 72724
    largiader.com bmwra.org

  7. #7
    Registered User R100RTurbo's Avatar
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    Shaft Rotational Play

    Quote Originally Posted by AntonLargiader View Post
    There have been plenty of '84s without the circlip. You can't tell without disassembly.

    The rotational play you mention isn't in the input shaft but rather in the gear dogs. If you have a broken input shaft spring, though, you will get more of it; I will try to remember to check a few of them this coming week to see what is normal. Normally the shaft has no play under hand pressure.
    r90s_shaft.jpg

    Ignoring the worn condition of this borrowed photo of an input gear assembly (photo from Jorg's tutorial), it would "appear" the flat nature of the gear dogs have some room to rotate freely between the spring seat dog radius "ramps".
    Shail's is just down the street, may drop by after work to see if he has a unit on the floor I can give a "twist".
    LW

  8. #8
    . AntonLargiader's Avatar
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    Under engine power, yes. Under normal hand pressure, no.

    In first gear, 80? input shaft rotation matches what I see on a transmission I have here. It varies depending on the gear you are in.
    Anton Largiader 72724
    largiader.com bmwra.org

  9. #9
    Registered User R100RTurbo's Avatar
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    That photo posted above is not accurate to my input shaft assembly, I took a look at one removed from a similar vintage transmission and concur with Anton's recommendations. The play I note is most likely the gear cogs which have generous slots to reside within when shifted.
    Hence, the old adage "if it ain't broke then don't fix it" and I'll leave the box together at this time as it has no known issues and is removed for a spline lube and clutch rework** (wouldn't mind pulling it down perhaps next season but will budget for some fresh internal items so that I don't resort to the reusability philosophy so heavily).

    ** working with a couple of paddle disc's, one is a 3 puck arrangement, the other is a 4 puck on a softer ceramic material - and a test cell to confirm torque holding characteristics. I haven't gone far enough to post any detail on that yet but will.

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