1978 bmw r75/6

Discussion in 'Airheads' started by d_mpls, Apr 14, 2012.

  1. d_mpls

    d_mpls Adventurer

    Joined:
    Apr 8, 2012
    Oddometer:
    72
    Location:
    44°59′N 93°16′W
    Hello I have been looking at buying an airhead for a while (i posted on this forum already asking advice)

    I found one (actually someone from this forum found it and sent me the link) that seems pretty interesting
    1978 BMW R75/6
    30,541 miles
    cosmetically ok, not great, it has a non matching windjammer.
    asking $3000

    I went to see the bike, all seems good to me with the exception of the following and i would like to hear some more experienced people tell me if i'm heading in the right direction or not.

    ISSUE 1:

    The is an oil leak coming from under the bike, initially i thought it was the oil pan gasket, but upon inspection i noticed that the oil comes from a wire/bolt on the left side (maybe the oil sensor). Initially the oil was just one drop, but after starting the bike i saw another 6-7 quickly coming down (especially after i pushed the throttle at higher rpm)

    here is the image of the bolt
    http://www.mediafire.com/?yg5a9wgqlsjk8p2

    here is the image of the area above the pan, which seems to have quite a bit of oil
    http://www.mediafire.com/?gujyrwpvzluz8z3

    ISSUE 2:

    The bike seems to take a little to warm up, is 2 minutes with the choke on too much before being able to have no hesitation, or common for this kind of bikes?

    ISSUE 3:

    When the bike was started some water dripped down from somewhere on the left side. I think it was from one of th exhausts, but the water was more or less near the center of the bike, odd. Can someone tell more about this? Common? Scary?



    Bottom line, Does it seem like a decent bike for the price?

    Thank you id advance people!
    #1
  2. bmwhd

    bmwhd God Bless Texas

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    #2
  3. ritetwist

    ritetwist Been here awhile

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    The switch is the oil pressure sensor,it has a gasket under it.I am not sure if it can be tightened,I'm quite sure it
    cannot be bought seperate from BMW.Probably have to change the switch(relatively inexpensive).

    The leak on the back of the pan is most likely from the neutral switch, quite common and much discussed.
    Seems to be a weak point.Check procedure to replace.

    On the warm up,some seem to take more time,I don't think that is a bad thing but some tuning may be in order.

    The moisture is from the exhaust (condensation).

    I am not sure about your model or year, you can check against the SN.
    Good luck.
    #3
  4. d_mpls

    d_mpls Adventurer

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    Oddometer:
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    Location:
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    Nice, thanks for the info!

    When you said ..."cannot be bought separate from BMW", what do you mean, that there is no after market?



    #4
  5. ritetwist

    ritetwist Been here awhile

    Joined:
    Jun 29, 2011
    Oddometer:
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    Location:
    North AB, CDA
    I would try an aluminum or maybe a copper gasket of the right size. ( 12 X 16 mm ?)
    #5
  6. Horsehockey

    Horsehockey A GPS? Huh?

    Joined:
    Nov 17, 2010
    Oddometer:
    365
    Location:
    Vermont
    First, what's the VIN number (stamped into the engine case, immediately above the dipstick)? That number will determine what year bike (engine) you're dealing with.

    http://bmbikes.co.uk/enginechassis.htm

    General comments:

    Second, for your planning purposes, if you actually want to "fix" everything that will have been neglected on the bike and make it really roadworthy, plan on putting about another $2K into it over the next year or two. A bike like the one you describe sounds like it needs a new oil pressure switch (the leak) and other deferred maintenance on a new-to-you airhead typically involves tires, battery, replace all lubes, any new cables needed etc. The oil accumulation on the "shelf" under the engine is either a leaky neutral switch, leaking rear main seal or leaking oil pump cover. None of this is a huge dealbreaker but the replacement or repair of anything other than the oil pressure switch is more involved. Lots of guys run their bikes with weeping in these locations....

    Use of the choke for a couple minutes in Minneapolis in April sounds about right. The "water" leak question is odd...maybe just condensation from the exhaust. That could be sorted out.

    If you would prefer to just buy a bike and ride, you probably should look for a newer bike. These old airheads can be brought back and can be superbly reliable for lots and lots more miles (mine has 96K on the clock now), but time, money and effort are required.
    #6
  7. gsd4me

    gsd4me 90% bluff

    Joined:
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    Oddometer:
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    Location:
    Brisbane, Australia
    If the bike is actually an R75/7 I`d be buying it in a flash. BMW didn`t make many 750cc /7`s before increasing the capacity to 800cc; They are quite rare.
    #7
  8. LonerDave

    LonerDave Been here awhile

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    The oil sensor sometimes leaks through the switch itself (where the wires come out). If that's the case, a new gasket won't help. I bought a replacement switch from Auto Zone for less the $10, IIRC. Equivalent parts are listed in a sticky at the top of this forum, or search. Take a closer look for the source of the leak before you buy parts.
    #8
  9. d_mpls

    d_mpls Adventurer

    Joined:
    Apr 8, 2012
    Oddometer:
    72
    Location:
    44°59′N 93°16′W
    Thank you everybody for the info and the tips, this is exactly the kind of help that i was looking for.

    I'm not looking for the perfect bike, in the end i love these airheads and i'm willing to put up with spending some money.
    #9