Hown can a '77 R75 tachometer be repaired?

Discussion in 'Airheads' started by skipn, Jul 24, 2012.

  1. skipn

    skipn Been here awhile

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    I have just started on trying to make a barn find road worthy again. It is a '77 R75/7 with 27,000 miles on it. Second owner's had it for 25 years, but it has been much neglected for the last 12 years while he was living in Germany.

    One of the things I'll have to fix is the tach. The speedo works, but the needle fell off the tach. It is gone, so the tach must have been opened up at some point.

    Any insight on how to fix it, find a good used one, or other options?

    Thanks for any help.
    #1
  2. Hoppalong

    Hoppalong Adventurer

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    A few years ago Palo Alto Speedometer fixed the speedometer from a '74 R90S I was restoring. At the time they had a good reputation in the local BMW shop, but I have no idea if they still do that type of work.

    http://www.paspeedo.com/
    #2
  3. DaveBall

    DaveBall Long timer

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    Palo Alto is still the place to have your speedo completely overhauled. They do great high quality work, but they are not cheap. Still costs less than new ones, which are getting harder and harder to get.
    #3
  4. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    ADV Inmate Wirespokes works on BMW instruments. He may even work on something as new as a '77...
    #4
  5. Wirespokes

    Wirespokes Beemerholics Anonymous

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    I work on all of the airhead speedos, and have replacement parts.

    Often when the needle is broken or missing, the mechanism has self destructed - they get violent and the needle just can't stand up to the abuse. Then with the needle out of the way, the mechanism really goes wild and things get messy in a hurry.

    I'd guess the tach needs a complete rebuild. But that's just my guess from little to no data.

    I would recommend servicing/repairing both gauges, along with checking/repairing the light board.

    Maybe seven years ago I bought a /5 (14K on the odo) from the original owner, a friend in Los Angeles, and rode it the thousand miles home. It had lived its life in his garage, but looked rough with corrosion coming on, faded paint, and some funky repairs. But the gauges worked. Half way home both gauges started acting up and before long they'd both started squealing and self destructed. They both needed total rebuilds. What a mess!

    The best course would have been to service the gauges in the first place and they wouldn't have needed new shafts, bushings, needles and springs. It was a real mess in there!
    #5
  6. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Yes, maintian it now and you'll save a lot of repairs later on. I'm doing that long-awaited maintenance on the forks in August, and I'll do that "other maintenance" that I've planned. Got a couple of bezels, too. {wink, wink}
    #6
  7. Hawk Medicine

    Hawk Medicine Coyote's Brother

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    Just so you'll know...

    Spokes did a great job on my instruments AND my tranny!


    Give him a call before you buy something on Ebay. Keeping things in the family is a good thing! :lol3
    #7
  8. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Thanks Hawk! :evil

    Bill - how do the bezels look? Worth the money?
    #8
  9. skipn

    skipn Been here awhile

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    Thanks for the info. I think I'll just disconnect the speedo and tach for now, and see how the bike comes together. Speedo works fine, so I'll lube the cables before it goes back on the road.

    It has been rather neglected-- second owner bought it in '87 with 19,000 but didn't ride it much after a couple of years since he moved to Europe for 12 years. Maybe a couple of hundred miles each year. Maintained something like this:

    "Valves checked 8 or 9 years ago-- at maybe 24,000, gear box oil changed in 1993. Oil changed every year before storage (doubtful since the oil was really black when I dumped it and it was obvious it hadn't been ridden in sometime)." Sat in a garage or barn for the last 3 years.

    So, I want to make sure the motor and tranny are solid before I move onto other things. I'm confident enough that they are, that i have new plugs & wires, filters, tires, brakes, brake line, fork seals etc. on the way.

    A working tach, battery side covers and tool tray would be a real plus along with a new exhaust, but I'll wait to see how it plays out. Frame and wheels are rust free, and the tank is looking good after finding a bit of rust.
    #9
  10. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Be sure to lube the cable ends - especially at the controls! You want those barrel ends to swivel in their sockets, otherwise the cable swivels... and breaks after a while. Ask me what it's like riding from the southern end of San Francisco, all the way through town, across the Golden Gate to Marin (while leaving the clutch lever alone) to get a new cable because mine was hanging by three threads. :eek1

    It took a while to get to that point, but it was a recently resurrected bike like yours.

    So learn from my stupidity!:wink:
    #10
  11. pthomas

    pthomas Been here awhile

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    Wirespokes,

    How do we get in touch with you? My gauges will definitely have to visit you at some point and I just saw that you also do transmissions and I'm about to open mine up to figure how what's wrong with it... it may need to see a specialist.
    #11
  12. skipn

    skipn Been here awhile

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    Thanks for the reminder. I planned to do that, but since you mentioned it, I went out and took care of it now, so I don't forget.
    #12
  13. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    "Worth" is a relative term. They're replacement parts that fit a speedo/tach on a bike that went out of production 40 years ago. Glad that they're still available. They _appear_ to be identical to the OEM bezels, but I have no idea how well they'll crimp. They do have a new bezel-to-glass o-ring. We'll see how they work.

    Also broke down and bought a ToasterTan upper fork piece. Figured that this wouldbe the ideal time to install one. Absolute piece of ART.
    #13
  14. skipn

    skipn Been here awhile

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    FWIW-- I guess I shouldn't call it a barn find because I think of that as something really valuable found in a barn and bought for next to nothing, like a '66 Corvette that's been there since 1969, and she wants $500 for it.

    Or just anything old, cool, and cheap. Mine qualified on the first 2 counts, but I probably shouldn't have paid as much as I did since I am going to have to spend more than I first planned. Well, I should qualify that by admitting I intend to fix it up better an I planned. Still, I hope to keep it a low bucks build, just for riding locally for grins.

    The day I brought it home:

    [​IMG]

    Boy, am I in deep stuff now.....

    [​IMG]
    #14
  15. Beemerboff

    Beemerboff Long timer

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    An alternative to BMW'S high instrument prices may be on the way - there are Indian made Replica G/S speedos on Oz Ebay.

    Correct ratio number and lettering but they forgot the trip, but for $70- you cant expect everything.
    #15
  16. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Send me a PM, or better, an email.

    Beemerboff - I've seen those gauges from India, only they've been for the pre-1970 models.

    skipn - nice looking bike! Must have been a very clean barn. Did the bike have a cover over it? Also, I think most of us paid too much for our first beemer - don't feel like the Lone Ranger!

    Bill - yeah, know what you mean about unobtanium bezels. I think that's the only one available any more. I've been trying to figure out how to reproduce the rest of them.
    #16
  17. pyropete

    pyropete n00b

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    I also have a 75/7 with about 23000 miles on it.On its first ride after winter storage this spring , the tach started chattering. It may be just the cable.
    I have been unable to get either the tach or speedo cables off of the instrument. The brass threaded section that the cables screw onto just spins when I try to remove them.
    any suggestions?
    If I do get them off , what should I use to lube them and the inside of the tach?

    Thanks
    Peter
    #17
  18. Beemerboff

    Beemerboff Long timer

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    A long time ago we used powdered graphite in the cables, as you didnt want oil working its way up the cable and into the Smiths Chronometric, or whatever, instruments.

    I would probably still work OK on the cables, but I have no idea either if the instruments need lubing or if they do, what to lube them with.
    #18
  19. Wirespokes

    Wirespokes Beemerholics Anonymous

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    You can't lube the instruments through the input where the cable attaches. They have to be dismantled to get to the lubrication points.
    #19