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Transmission seal replacement

Discussion in 'Motorcycle Tech Talk' started by shovelRob, Apr 20, 2011.

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  1. shovelRob

    shovelRob New Member

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    Finally got a tool borrowed to take off the sprocket nut. Old seal has to be removed to take it off. I'm not even sure that's where the leak is, if you want to know the truth.

    The old one looks like two fitted together. The new one is too small, the shop I got it from said , "Oh, late 79. That's different. He's going to swing by the HD dealership in Salinas on his way home and get me one.

    Minutes between everything, I just might have this thing running soon.
    shovelRob, Apr 20, 2011
    #1
  3. chucktx

    chucktx Moderator Staff Member

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    good luck with it~~
    chucktx, Apr 20, 2011
    #2
  4. hotroadking

    hotroadking Super Moderator Staff Member

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    I put them in freezer for hr or two. Shrinks them down for easier install


    Sent from my iPhone using Tapatalk
    hotroadking, Apr 20, 2011
    #3
  5. shovelRob

    shovelRob New Member

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    I put it in the freezer as suggested. It was also suggested I apply some silicon to the outer part of it.

    Drove it in with a piece of 2" pvc with an end cap for hammering on.

    I still need to assemble the rest, but this part went well. I forgot that the bearing on the inner primary got pretty toasted at some point.

    I'm not really convinced that the leak was coming from the seal, so I plan to check all the primary hoses and fittings, as well as everywhere else on the trans. It seemed too thick to be regular engine oil. I hate a leaky transmission, so I'd like to really do this right.

    Thanks for the pointers.
    shovelRob, Apr 25, 2011
    #4
  6. Tommyc

    Tommyc Active Member

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    Guys, I am getting fluid inside my primary cover. :wtf:
    I converted to a belt drive to eliminate this exact problem. :wtf:
    Is the fluid coming from my tranny out the seal near the sproket, thru the bearing on the inner primary and then into the primary? :wtf:
    All I can say is: :wtf:
    I don't think fluid could be coming from anywhere else. :wtf:
    :wtf::wtf::wtf:
    Tommyc, Apr 29, 2011
    #5
  7. hotroadking

    hotroadking Super Moderator Staff Member

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    what kind of fluid
    Gear oil or engine oil

    Typically if your primary is filling with oil
    you have a bad seal behind the stator on the mainshaft/crankshaft
    and oil is flowing out of the engine into the primary.

    Transmission is behind the belt/chain pulley and
    for fluid to make it there it would dang near impossible.

    You must be flowing oil back in from the engine...
    hotroadking, Apr 29, 2011
    #6
  8. Tommyc

    Tommyc Active Member

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    Hummm. I didn't think about that.
    How do I tell if it's gear or engine oil.
    Tranny is using cycle trans fluid and engine is 70 wt.
    Tommyc, Apr 29, 2011
    #7
  9. hotroadking

    hotroadking Super Moderator Staff Member

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    Well drain trans, put in gear oil

    or

    go to autoparts store and get some dye
    you can put it in fluids and run the engine
    when the oil fills the primary you'll see the dye..

    JMO it's your engine mainshaft seal that's gone
    and leaking, pull the rotor and check the back see if it's oily

    Also Drain the primary check qty, then drain engine, bet it's low.

    Trans holds one qt so if you pull a half qt out of the primary
    and the trans dipstick says full......
    hotroadking, Apr 29, 2011
    #8
  10. Tommyc

    Tommyc Active Member

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    When the primary was apart I rememebr seeing fluid coming from behind the rotor. I was like WTF but didn't think it was coming from the motor.
    How hard it that seal to replace? Do the case have to be split?
    Tommyc, Apr 29, 2011
    #9
  11. hotroadking

    hotroadking Super Moderator Staff Member

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    IIRC the seal is on the outside (inside primary) and could be replaced
    without taking the engine apart. Remember i'm going by Evo/TC standards
    not much shovel experience but I'm figuring HD hasn't changed some things for 40 years
    and they probably still put the seal on the primary side.

    Although you are going to have to take the primary apart...
    hotroadking, Apr 29, 2011
    #10
  12. Tommyc

    Tommyc Active Member

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    This is a pic of my parts..
    Whata pain in the a$$. I think I will wait till next time I take it all apart. Planning to do that soon when she gets repainted.

    Attached Files:

    Tommyc, Apr 29, 2011
    #11
  13. hotroadking

    hotroadking Super Moderator Staff Member

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    well the oil could destroy the belt, it's not supposed to be wet,
    or lubricated.

    JMO next rainy day I'd have it apart...
    hotroadking, Apr 29, 2011
    #12
  14. Tommyc

    Tommyc Active Member

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    I can get at it but I'm just wondering how to pull that seal from off the shaft? Is it on the outside surface of the case.
    Tommyc, Apr 29, 2011
    #13
  15. hotroadking

    hotroadking Super Moderator Staff Member

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    Have to check with the resident shovelistas on the board...
    hotroadking, Apr 29, 2011
    #14
  16. Tommyc

    Tommyc Active Member

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    Whom might they be?
    Tommyc, Apr 29, 2011
    #15
  17. hotroadking

    hotroadking Super Moderator Staff Member

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    Shovelhead forum post on leaking seal

    It's a function of bad seal or improperly installed
    or too much pressure in the engine...

    SNS makes replacement parts you might check dealers in the area
    to see if any have the parts, and when you drop off the carb
    question John he might have the seal and give you instructions...
    hotroadking, Apr 29, 2011
    #16
  18. Tommyc

    Tommyc Active Member

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    Ah ha, could my problem be from the tubing I have that goes from the heads down into the crank case via the timing mark hole? See pic..
    That could case too much pressure inside crankcase and force oil out thru shaft seal, yes?
    I think you might have stumbled upon the soultion to my problem. Maybe I should reroute the tubing from the heads to connect to the crankcase vent over by the oil pump?!?

    Attached Files:

    Tommyc, Apr 29, 2011
    #17
  19. hotroadking

    hotroadking Super Moderator Staff Member

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    It would appear that over pressure in the cases is the main
    culprit,

    I would not vent heads to the crankcase and add pressure
    to the system, the pistons create pressure on the way down and are probably
    fighting the heads breathing out...

    Do you have the cases vented from the bottom via hose to a
    filter or flapper on the end of the hose?

    I would run the heads to a separate line/hose, down the back of the frame, behind the oil pan and put a cci filter on the end, or route best way to hide.

    two vents will relieve pressure, we opened up the crank vent on Dougs 113 El Bruto as it was causing pressure leaks when we put in new pistons with better seal...
    hotroadking, Apr 29, 2011
    #18
  20. Tommyc

    Tommyc Active Member

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    Yes I have a filter on a hose from the case vent. Looks like it time for another one!
    Thanks Buddy!!
    I will let you know if it works!
    Tommyc, Apr 29, 2011
    #19
  21. hotroadking

    hotroadking Super Moderator Staff Member

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    heads and cases should have separate breathers for max pressure release
    hotroadking, Apr 29, 2011
    #20
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