Build thread blah blah blah R75/6 "Ernst"

Discussion in 'Airheads' started by melville, Jun 23, 2010.

  1. melville

    melville Long timer

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    This morning's anti-progress. I was having trouble detailing the case between and above the PR tubes, so I took the top end off for better access:

    [​IMG]

    No not really--I had other issues, particularly on the left side. Motor sat for a couple years at BDC with a valve open on the left side, leading to this:

    [​IMG]

    While it ran OK last summer, and compression improved dramatically in the 10 miles I ran it, it was still not right. I'm hoping a good honing and rering will straighten it out. I'm not oppo$ed to going first oversize, either. I'll see what the machinist says.
    #61
  2. melville

    melville Long timer

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    And the machinist ran the hone through the cylinder and pronounced it CRAP. We're going to bore it out.

    I brought the sump extension to my local airhead guy and he spot faced the holes that had gotten funked up from running loose. I've just gotta make a coupla gaskets and put it back together mit Loctite and the sump can go back on.

    Meanwhile, progress continues. I made a fixture for my dial indicator to check parallelosity of the fork stanchions, and in so doing I became acquainted with a previously unknown to me local resource--the Boiler Works!

    I needed a short piece of 2" AL angle thick enough that I could tap it M8 through the bend and I was not finding it at the hardware store nor at the machinist. The machinist sent me to Boiler Works, which was not far from home. They had buttloads of all sorts of metal bits and hooked me up with this remnant for less than $3:

    [​IMG]

    I'm now looking for projects around the house that will require a trip to Boiler Works just so I can walk around the BIG room full o' metal some more.

    All drilled and tapped and indicator installed:

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    And checking the fork. Top:

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    And bottom:

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    I'm pretty happy with <.001, and it was still straight in the plate glass plane. Someday I'll be able to start with the sliders and front wheel.

    After that it was time to put the top of the fork together. I was a little surprised to find that BMW relied on the chassis ground all the way out to the front turnsignals. I had to check continuity at every step before I believed it, and I had to remove the PC on the TS stalks to get continuity in the pods.

    [​IMG]

    Once that was together it was time to monkey with the headlight bucket and the main harness. Success! I'll probably install the battery with a coupla jumpers to check the lights and whatnot:

    [​IMG]

    But there is trouble. I don't have a good picture of where the wires connect on the starter relay because they were all the same color (coppery green) when it came apart due to the leaky MC. When I cleaned the relay I was distressed to find that there were no DIN numbers on the bottom. Can any one tell me what goes where on this thing?

    [​IMG]

    [​IMG]

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    Last pic is as if you removed the screws that hold it to the frame and tilted it up to see it. Any help much appreciated and I'll fax you a beer.
    #62
  3. blaine.hale

    blaine.hale Long timer

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    #63
  4. melville

    melville Long timer

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    Yeah, I've got that same diagram in my Haynes--trouble is I'm not sure which numbers on the relay in the diagram go to which prongs on the relay in my hand. I can play with running 12V through it and seeing what makes clicks and whatnot but that's really just risking an electrical fire under 6 gallons of gasoline :yikes
    #64
  5. anonny

    anonny What could go wrong?

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    Maybe put a brass wire wheel on a drill and spent some time cleaning it the numbers may come to surface, and it wont hurt those spade connectors a bit (if your gentle)
    #65
  6. bmwhacker

    bmwhacker Still on 3 wheels

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    I ended up with the same "starter relay wiring I.D." problem on my R100S - /6 BMW build...ended up taking the tin cover off the starter relay and identified the individual componants by comparing to the wiring diagram of the relay....I had a slightly better detailed wiring diagram of the relay than seen in this thread. In any event it was sorted out.....:clap
    #66
  7. melville

    melville Long timer

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    This helped a lot (thanks to G Ryals!):

    http://www.airheads.org/content/view/159/98/

    It includes a schematic showing physical layout of terminals and colors going to it.

    Meanwhile, I got my lever perches back from PC, and after foodling about with them, got them installed:

    [​IMG]

    [​IMG]

    And or course, once installed, I had to check the fit:

    [​IMG]

    I do have enough bits in process, here and elsewhere, to make it a roller, but not everything has made it home yet. Mrs. melville has offered to push me around on the dolly, but she'll require me to make MC noises to do so.
    #67
  8. matman1972

    matman1972 Lost in the woods.

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    Go speed racer!!
    #68
  9. east high

    east high Been here awhile

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    Someone needs to photoshop this.
    #69
  10. Jasper ST4

    Jasper ST4 Guest

    The wheels are too small. It's gonna handle like crap on the freeway.
    #70
  11. bmwhacker

    bmwhacker Still on 3 wheels

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    The "Tenny's" look fast just sittin there!:eek1
    #71
  12. melville

    melville Long timer

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    Yeah, I was gonna get the rest of my ATGATT, but my young photog didn't have time for that much Daddy silliness. Impatient little rascal.
    #72
  13. RLieu67

    RLieu67 Adventurer

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    [​IMG]:D
    #73
  14. bpeckm

    bpeckm Grin!

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    and beware the front end fork dive :wings
    #74
  15. east high

    east high Been here awhile

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    [​IMG]
    #75
  16. melville

    melville Long timer

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    We (Mrs. melville and the boys also) bow to you, sir! Well played! ROTFLMAO! :bow
    #76
  17. matman1972

    matman1972 Lost in the woods.

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    doncha know, that in order for Chuck taylors to be approved safety equipment for airheads, they have to have racing stripes.

    [​IMG]
    #77
  18. noman

    noman Long timer

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    hello!

    am closely following your build as i just bought back my 76 r75/6 and it needed a thorough cleaning and mechanical refresh after sitting (with a full tank of gas, thank god). am done and it's smooth as silk, my daily ride once again.

    congrats on your progress so far, very cool. wanted to thank you for some hints on gen'l assy, and also inspiration for my winter projects -- painting the headlight bucket (am red/green color blind) and suspension upgrades. nice work, man.
    bobp
    #78
  19. melville

    melville Long timer

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    I do have a pair mit stripes somewhere. Someone gave me a custom shoe gift card and I made the mistake of picking the colors with my then 6-year old. Ended up looking like clown shoes......

    Today's goodtimes. Got to cleaning/refinishing the transmission. Started out like so:

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    [​IMG]

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    After a couple hours of Simple Green, Brakleen, and ScotchBrite both without and with paint I've got this:

    [​IMG]

    [​IMG]

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    I also cleaned and regreased the throwout mechanism which runs through the input shaft. Then I made a flywheel lock:

    [​IMG]

    I was annoyed to find that BMW used M8 X 1 fine thread for the clutch bolts. I thought only us bicycle people had to deal with that sorta thing. How long a bolt do I need to release the pressure safely?
    #79
  20. melville

    melville Long timer

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    Found out why the clutch was so abrupt. These two are stuck together--not coming apart:

    [​IMG]

    Now clearly they were capable of motion relative to each other last summer, or I wouldna been able to ride it the little bit that I did, but the clutch did engage with a loud "squartch" sound.
    #80