1974 BMW R90 /6 Rebuild & Modifications

Discussion in 'Airheads' started by fadingfastsd, Oct 30, 2010.

  1. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    Hey guys,
    Not new to ADV, or Airheads by any means. My last airhead was a 77 R100 /7 about 3 years ago. Had many different bikes since then, but now I'm back to airheads haha.

    I just recently sold my 86 GSXR 750 that was my daily rider. I was ready for another bike, but was done with sportbikes for the time being.
    I came across this 74 R90 in my area, and went to take a look.
    I ended up $2k, which I now think was a little high after getting it all apart.
    Overall it is in completely solid mechanical shape. It started easily, and ran fine.

    So far I have the whole bike torn down, engine in frame. Changed ALL fluids, new cables, new brakes, new tires, clean carbs, set valves. Trying to figure out what low bars I want to put on. Going to do a mild cafe build on it. Ditching the battery tray and huge battery, ditching the side covers.

    I'll be doing some interesting wiring on this bike too. I used be the R&D manager for Electrosport, and am really familiar with Acewell speedometers. I also do consulting work for Baja Designs, who is the new distributor for Acewell speedo's. So I'm going to get 2 Acewells, and run them as my new dash. Probably a round 2800 series, and a rectangular 3000 series side by side.

    Will be using LED turn signals, LED taillight. I may convert the rear to single shock as well.

    Anyways, here's some pictures, I'll keep you guys posted.

    Is this tank correct for this bike?
    Also, anybody have a stock seat? It has this single oldschool seat, which is not my style.

    [​IMG]

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    [​IMG]

    [​IMG]

    Luftmeister Fairing for sale! Make offer, I'll take anything!
    [​IMG]

    Krauser hardbags with brackets for sale! Make offer, I'll take anything!
    [​IMG]

    [​IMG]

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    #1
  2. east high

    east high Been here awhile

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    Oct 13, 2009
    Oddometer:
    955
    Location:
    Portland, Oregon
    I'm interested in that little rack if you don't want it. :evil
    #2
  3. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    Tank's a correct small tank. There's also a large tank for these years.

    PM'ed about parts (tac/sidecovers/Krausers).
    #3
  4. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    I'm looking for a larger tank in nice shape, and a stock bench seat.
    Will trade the parts you guys want, including fairing and/or Krauser bag set for seat or tank.

    I might sell that little rack, not sure if I'll reuse it. How much?
    #4
  5. vernon dent

    vernon dent Been here awhile

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    Oct 9, 2010
    Oddometer:
    709
    Location:
    apparently halfway to motorcycle hell
    if you bought that bike for $2g's i think you did very well. i'd love to buy the stock turn signals and solo seat if you'll be selling them.
    thanks
    #5
  6. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
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    9,116
    Location:
    San Francisco Bay area
    Fadingfastsd, a friend of mine had a super motarded out ATK that had a Baja lighting kit. I always thought those rechargeable AA batteries wired up for 12 volts were genius! What a small package and they worked!

    I have a project that is needing a speedo. I'll be watching this thread!
    #6
  7. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    You really think that $2k was a fair price? I don't think it was a complete rip off or anything, just after getting apart it was rougher than I thought. I wish I would've paid closer to $1500, but oh well. It's coming along just fine.

    I've decided I'm going to take a 4-5 day ride in a couple weeks after I get this thing dialed in. Not sure where exactly yet, but it'll be fun.

    I need to sell alot of these parts to fund this rebuild.
    I'll get some better pics of the Krausers, they are kind of rough. All the brackets are there though.

    I have 2 of the solo seats, as well as that little luggage rack.
    I'll take detailed pictures and post them tomorrow with prices.

    What other tanks are interchangeable with this frame?
    I'd like a larger tank for sure.
    #7
  8. wirewrkr

    wirewrkr the thread-killer

    Joined:
    May 23, 2008
    Oddometer:
    4,295
    Location:
    HIGH desert

    If you head East into the desert, come on up to Joshua Tree, The wine's on me and I'll let you use the shop for any adjustments you may need to make.
    Robert
    #8
  9. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    Hey Robert, thanks for the offer man! I haven't been to Joshua Tree in a long time. I used to go camping out there and do some rock climbing, but it's been years since I've done that.

    I think I'll come back through JT area though, that's a great idea. I'll keep you posted.
    #9
  10. blaine.hale

    blaine.hale Long timer

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    Feb 28, 2009
    Oddometer:
    3,281
    Location:
    Atlanta, Ga
    I don't get it. Why would you rebuild a 1974 r90? Rubbish..
    #10
  11. Sniper X

    Sniper X De Oppresso Liber

    Joined:
    Jul 18, 2006
    Oddometer:
    33,351
    Location:
    Central New Mexico, 7420ft above sea level
    BUT, did you get both the key for the bag and the key for the lock to lock them to the bike? What numbers are on the keys if you DID get them? I can reference that number for vintage of the luggage.

    thanks,

    Kevin
    #11
  12. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    #12
  13. SO CAL CHARLIE

    SO CAL CHARLIE Adventurer

    Joined:
    Jul 26, 2010
    Oddometer:
    23
    I Might Be Getting A R 90/6 Doner Parts Bike....... Need Stuff ?[​IMG]
    #13
  14. fadingfastsd

    fadingfastsd Been here awhile

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    Feb 17, 2007
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    262
    Location:
    San Diego, CA
    Awesome yes!
    I'm interested in a good seat, rear shocks, fork rubber gaitors, handlebar controls/switches, tach/speedo gauge cluster...

    any of those available?
    #14
  15. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    Ok couple things. I'll post some more pictures tonight (I'm in class) of the current progress.

    I don't think I mentioned it above, but I'm ditching the battery tray for sure.
    The old battery had leaked all over it, and the acid had trashed it beyond hope. I'll be welding up a new tray.

    I picked up a cheap battery today, however it is a small 12Amp/Hour battery, a CB12-AL. I'm hoping this will keep up OK, the service manual spec'd a 25AH for this bike. However, I'll be running all LED turn signals, LED taillight, Acewell speedo (uses less power than the backlighting in the stock speedo), and an HID headlight (35W hi/lo). We'll see if this battery will work...

    As for handlebars, I really want a set of R65LS bars, like I had on my old 77 R100. Couldn't remember what they were, and I posted another thread (here) and awesome ADV'ers helped me figure it out. I'd like to get another set, but my local dealer has to order them from Germany, which will take 3 weeks.

    I want low cafe-style handlebars, but I don't plan on doing rear sets (yet).
    I'm considering clubmans, but past experience is they are pretty uncomfortable. I'm looking around a little more, but I might just bite the bullet soon and order the R65LS.
    For mockup now so I can run cables and figure out wiring, I cut in half the super high touring bars that were on it, flipped them side/side, and bam! instant cafe bars. haha it's kind of ridiculous, I'll post a pic showing you what I mean.

    Tires and new brake shoes & pads should be here tomorrow. I went with Bridgestone Spitfires in metric sizes from Dennis Kirk. About $55 each, not bad.

    Front:
    [​IMG]

    Back:
    [​IMG]

    I have a set of carb kits from EUBMW coming too. I cleaned and rebuilt the carbs already, but all the rubber was trashed. Put them back together and they leaked. So, they're back off and getting all new rubber.
    Oil change tomorrow, and new gear oil in shaft and final drive.

    She already got new plugs, condenser, points, set point gap, set valves, new battery cables.

    I need to figure out electrical issues now. The wiring harness for the fairing was not installed correctly. Headlight and turn signals did not work. Both of the handlebar switches are bad inside as well. Start button is intermittent, horn button doesnt work. I think I'm going to ditch both old switches, and replace with new switchgear I have. I have to build a new wiring harness for the HID ballast as well, to be triggered from the stock headlight connections, as there is no H4 bulb connector in the headlight bucket (removed for fairing).

    I'm interested to see if the diode board and voltage regulator are OK. I may dump those and build my own solid state Regulator/Rectifier. I have an updated design I began working on when I was running R&D for Electrosport. Was laid off when the company went under in April, not to mention completely screwed over by the new owner, so needless to say I'm not a fan of the company anymore. Anyways, I'd like to handbuild my own R/R unit, so I just may do that.

    On a side note, does anybody have ANY rear shocks for sale? Well used is fine, but something in decent shape? The set I have on here are trashed! Please let me know.

    Also, it looks like I'll have a spare Acewell computer for sale, maybe 2.
    Let me know if anybodys interested. I would trade an Acewell for shocks too!

    Pics coming later tonight.
    #15
  16. danedg

    danedg Horizontally Opposed

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    6,793
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    I got 9000 miles out of my rear spitfire....the front is still on after 15....
    great tires.....:deal
    #16
  17. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    Other way around for me with Metzelers. Maybe I should try your brand on the rear..
    #17
  18. fadingfastsd

    fadingfastsd Been here awhile

    Joined:
    Feb 17, 2007
    Oddometer:
    262
    Location:
    San Diego, CA
    A few more updates.
    Got my tires today. Also got new brake pads in, (rears installed today, still need to do fronts).
    I got my HID headlight wired up and working correctly. Cleaned the handlebar switches.

    Just waiting on carb kits to get here from EUBMW.
    How long does their shipping usually take? Still waiting....

    As for tires, will most car tire shops mount & balance bike tires? Just wondering.

    And some pictures:

    Here's the handlebar setup I was talking about. This is completely temporary, and won't be ridden like this. Just couldn't stand looking at the high bars any more, this let me route the cables.
    [​IMG]

    On second though, just figured I'd ask. If I weld the bars back together between the clamps, think this would be OK to ride?

    Brake pads:
    [​IMG]

    New tires (Bridgestone Spitfires)
    [​IMG]

    Widened the hole in the bottom of the headlight bucket (was there for the Luft fairing wiring harness) and ran the wires for my HID headlight triggering through there.
    [​IMG]

    Shows the HID bulb in the housing. Had to trim down the bulb housing slightly to fit the housing. It's an H4 style, but slightly larger housing.
    Also I can sketch up a diagram of my relay and trigger setup for the HID if anybodys wondering.
    [​IMG]
    #18
  19. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

    Joined:
    Nov 28, 2006
    Oddometer:
    7,652
    Location:
    El Segundo, CA
    Why'd you cut the bars in the first place? :huh

    It's cool looking to be down so low, but sucks in city traffic.. I ditched my clubmans on my R90:
    [​IMG]

    ..and am now running some euro bars from Huckys. No complaints.

    [​IMG]
    #19
  20. bpeckm

    bpeckm Grin!

    Joined:
    Apr 2, 2008
    Oddometer:
    6,097
    Location:
    Road Island
    re Bars: you would probably find them difficult in tight situations, over to one side or the other....

    As mentioned: the Euro bars, or the 65LS bars, make great looking and functional bars.

    I am using K-bike bars, which also work fine, I used them on both of these bikes:
    [​IMG]



    :D
    #20