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Thread: Torque Values for the Oil Pump Cover - 1972 R 75/5

  1. #1
    Registered User b25bsaboy's Avatar
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    Torque Values for the Oil Pump Cover - 1972 R 75/5

    Good evening and Happy New Year to you all,

    Finally got to stripping the flywheel off, cleaned the cavity area of 47 years of dirt and grim in behind it. Te main seal has been replaced and the oil pump cover removed to replace the o-ring that sits on the circular dove tail land.

    Went looking for the torque specifications and Lord Ive looked to no avail in finding them. Does anyone know what the proper ft/lbs would be Phillips tapered screws?

    The R 75/5 internally thus far looks in very nice condition overall with very little wear showing.
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 73 R75/5 SWB, 2008 Honda GL-1800 Lehman Trike

  2. #2
    Registered User GTRider's Avatar
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    The information you need, along with much more, is here: http://bmwmotorcycletech.info/flywhe...valwarning.htm

    As Snowbum points out, you really want to replace the Phillips head screws and corresponding cover with the new-style cover and bolts. Torque values are in the article.

    Best,
    DG
    DGerber
    1983 R80ST 1984 R80 G/S PD 1993 R100GS 2004 K1200GT w/Hannigan S/C 2010 K1300GT
    BMWMOA#52184, AMA#271542, IBA#138

  3. #3
    I have seen it recommended that the "+" panhead screws on the /5 oil pump cover be replaced with socket cap panhead screws. See video from boxer2valve #4 [In video the old "+" screws were reused and a wrench was used to apply hand torque.] As I recall, on my /5 I also reused the "+" screws and used an impact driver to tighten - one whack with a hammer on the impact driver was used.

    https://www.youtube.com/watch?v=TPNF9T-4XTQ

  4. #4
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    If i remember correctly, i torqued those bolts to 84-96 inch pounds, on my /6. I also used a drop blue thread lock.

  5. #5
    Registered User b25bsaboy's Avatar
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    Quote Originally Posted by GTRider View Post
    The information you need, along with much more, is here: http://bmwmotorcycletech.info/flywhe...valwarning.htm

    As Snowbum points out, you really want to replace the Phillips head screws and corresponding cover with the new-style cover and bolts. Torque values are in the article.

    Best,
    DG
    Thank you for the response to my question. Read what Snowbum wrote that brings up a question:

    Early pump covers did not seal well due to excessive groove depth; installing the later type cover fixes that problem, by a change in O-ring groove depth and using the later thicker O-ring. If you have a Phillips-screw type of cover, I recommend you install the later pump cover, with the later hex-head bolts.

    Two questions:

    1. Whats the difference between the original oil cover plate verses the newer designed plate?

    2. On my 1976 R75/6, I had the exact same older style oil cover plate and Phillips-screw type screws with no leaks after reinstalling the new red o-ring. If I am correct the up-dated o-ring material and outer diameter size has been changed up, thus the standoff compression when the plate is fitted gives a better seal when torqued to the body. This maybe therory on my part as I have not gone a measured the old o-ring verses the new red coloured one.

    I guess I am from the old school. If it aint broke, why are we trying to fixit?
    Rick MacPherson
    Success is Not a Destination, But a Journey.
    Accredited Motorcycle Appraiser
    1968 BSA Starfire, 73 R75/5 SWB, 2008 Honda GL-1800 Lehman Trike

  6. #6
    Excess groove depth evades the normal logic of this design. Larger O ring cross section may cure that.

    That said, this is a simple design which is usually highly reliable. The plate tightens against the engine case until it is solid metal-to-metal with the squeezed O ring in its groove tightly sealing. The fastener cap screws need to be sufficiently tight to not loosen, and/or ought to be retained with thread locker so as not to loosen. But once the plate is metal to metal against the engine case with the captured O ring, further tightening of the fasteners does nothing but damage threads. You can't squeeze the two metal parts any more together than they already are.
    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/

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