Results 1 to 8 of 8

Thread: Final drive question

  1. #1
    Registered User
    Join Date
    Sep 2011
    Location
    Western Colorado
    Posts
    44

    Final drive question

    Got a problem on a 77 R100RS with the final drive blows oil out of the vent on top can the vent be taken out and cleaned the oil level seems right at the fill plug not sure whats going on any ideas thanks

  2. #2
    They sometimes do that with abrupt temperature changes, especially when cold, or with changes of altitude. It is possible that moisture entrained into the gear oil may cause foaming, but sometimes air just gets chopped into the oil increasing its volume.

    I've had it happen once on a bike and never again in 100K miles, on more than one different bike. I would be suspicious of moisture though, so changing the gear oil might be in order.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  3. #3
    Registered User
    Join Date
    Jan 2006
    Location
    Wisconsin and Florida
    Posts
    406
    Did you experiment with gear oils - must use same weight of gear oil BMW specs

    I tried 85w 140 once in the hopes it might stop some migration from
    rear drive forward into driveshaft area.

    The heavier 85w140 would sling up and come out the vent - switched
    back to 80w90 and all ok again

  4. #4
    Registered User
    Join Date
    Sep 2011
    Location
    Western Colorado
    Posts
    44
    thanks guys I'll try those things not sure what weight oil is in there as I just bought the bike this fall and yes it was cold today

  5. #5
    Make sure your seal is good between the driveshaft and the final drive. I had gear oil venting and ot wound up being the nut securing the pinion gear on the fd came loose and the driveshaft oil made its way into the fd and relieved. The final drive oil level always looked fine but if I.drained the driveshaft oil it was always low. It's easy to take the final drive off and check
    // 1975 BMW R90/6 (cafe'd) // 1957 BMW R60 (in pieces) // 1967 Aermacchi/H-D Sprint 250 SS (custom special) // 1967 Moto Guzzi V700 (current restoration)

    http://symphonyofshrapnel.blogspot.com

  6. #6
    Polarbear Polarbear's Avatar
    Join Date
    Jan 2006
    Location
    Clovis,CA
    Posts
    4,220

    Gl5,

    Its been for along time now,GL5 is used in most aps, less frothing, better overall than previous GL4s. Be sure you know whats in there? All my miles, never had this happen but yours clearly is, so! Some easy checks are in order; vent, drive shaft housing oil not migrating back, not much else. Good luck, Randy

  7. #7

    Final Drive leak

    Quote Originally Posted by Typ181R90 View Post
    Make sure your seal is good between the driveshaft and the final drive. I had gear oil venting and ot wound up being the nut securing the pinion gear on the fd came loose and the driveshaft oil made its way into the fd and relieved. The final drive oil level always looked fine but if I.drained the driveshaft oil it was always low. It's easy to take the final drive off and check
    I've just discovered the same problem on my R90S. I picked up a seal and a tool from Cycleworks.net that will allow me to tighten the nut to spec.

    DaveM
    1975 R90S
    2000 R1100RT

  8. #8
    keelerb
    Guest
    I found a nice solution here. Works a treat.

    http://advrider.com/forums/showthread.php?t=508781

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •