Bringing 74 R90S back to life after sitting 30 years

Discussion in 'Airheads' started by _cy_, Sep 30, 2011.

  1. usafe7ret

    usafe7ret Been here awhile

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    Dr T and SS you guys need to get a room and stop hijacking this thread!


    _cy_

    You had me going there for a minute wondering what kind of polish you would use to make the R90/S look like a blue DS bike!:rofl

    Good luck with your project. I am muy celoso.
    #41
  2. kbasa

    kbasa It's good to think. Super Moderator

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    Please stay on topic. I have better things to do than play kindergarten teacher for a bunch of adults.

    Random crap pruned and sent to Exploding Heads.
    #42
  3. Renner

    Renner combustophile

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    +1
    we need to let _cy_ have his thread back.

    edit: thx kbasa
    #43
  4. _cy_

    _cy_ Long timer

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    OK... back to serious business of getting this beast back to 100% mechanical condition.

    went with a smaller gel cell battery, lower weight with better cold crank amps is good by me.
    original battery cracked from freezing. all the acid dripped out. really surprised there's not more damage. battery tray is coming out for bead blast and paint.

    [​IMG]

    surprisingly I cannot find any damage under the battery tray

    [​IMG]
    #44
  5. _cy_

    _cy_ Long timer

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    a bit more progress

    1. making a wheel balancer
    2. polish rim and scotch brite spokes
    3. check rim for true and even spoke tension

    [​IMG]

    still need to purchase precision bearing on both sides. wheel has to turn with little to no friction

    [​IMG]

    [​IMG]

    [​IMG]

    Aircraft cable tensiometer used to check spoke tension. an even tone when each spoke is struck also is a good way to check tension.

    [​IMG]

    a dial indicator will be clamped to frame

    [​IMG]
    #45
  6. Solo Lobo

    Solo Lobo airhead or nothing

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    Cy,

    Love the bike and am very much enjoying the progress you are making.

    I would echo what supershaft said earlier... start with getting the bike running to assess the condition of the top end and transmission.

    If the cylinders need boring, heads worked on and transmission rebuilt ( which would not be much of a surprise given the long storage in the conditions you list) you are talking about spending a few $k's...

    The bike will be worth the investment, but you may find you are not an "airhead" guy after some miles.

    Assess the mechanical health first, and do everything else second
    #46
  7. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Excellent advice, Solo.

    Also, knowing the condition of the engine, transmission, etc, will allow you to predict and plan for future expense. Some of these things take time, in which case you won't find yourself next spring when bike fever hits hoping the (********) comes back soon so you can get the bike back together and ride it.

    Everything is most likely fine on the bike, but why not test ride it and know for sure?
    #47
  8. _cy_

    _cy_ Long timer

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    that's exactly the plan ... fixing flat tires and installing new battery are on my list before starting motor. still got filters, change out oils, tear down carbs, new brake master cylinder, rebuild front calipers, new front pads, etc.

    while the wheels are off doesn't make sense not to service rest of wheel while I'm there. still need to re-pack bearing before installing new tire/tube.

    LOTS more to go before starting motor and trying out tranny.
    hopefully will be there before too long...

    I have faith...there will be nothing wrong inside.
    #48
  9. Solo Lobo

    Solo Lobo airhead or nothing

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    :thumb

    I see where you are coming from, it it were me I would rebuild the carbs, jump to another battery and see what noises it made... at least that's what I did with my G/S when I puled it out of long-term leaky storage imposed by the PO (and a few motorcycles before that as well :D)
    #49
  10. supershaft

    supershaft because I can

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    Thanks for that echo SOLO LOBO. Tires? I would make sure I have an engine first! Then a transmission.
    #50
  11. disston

    disston ShadeTreeExpert

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    Your doing just fine. They all want to know if your engine and trans are OK or they can start feeding on the remains after you decide to give it up. :evil Fix the wheels and clean the gas tank. I can see what you are doing and it will have more cohesiveness as you make more progress. Rebuilding the carbs, maybe just a light rebuild, right away is cool too. And of course I would have new oil in in before the first crank. It's gonna go. I've done this before and they want to live. Well hopefully.

    Did you rinse the tank yet? It should be rinsed pretty good at least. How much crud was in it? Should replace fuel lines. pretty cheap to do. They old rubber will be very bad after 30 years. Maybe check petcocks?

    Very soon after she fires up you're going for a ride. That's what I do. I have that little stuff out of the way before starting because I'm not going to grease a wheel bearing after she fires up. We are moving out.
    #51
  12. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

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    I don't think I've ever seen a thread where people nitpick one guys resurrection process so much.

    True story: yesterday, I picked up a semi-basket-case airhead, and guess what I did today? Installed the headlight and turn signals. Oh no, I didn't tear the engine down first!! :huh
    #52
  13. supershaft

    supershaft because I can

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    Nitpick? Who's nitpicking? I just think it wise to make sure you have an engine and transmission before you start cleaning spokes. It would be a shame to get the thing all cleaned up and then not have the money to get it running for it needing new pistons/cylinders, valve job, and a tranny rebuild. That could break a heart! :cry
    #53
  14. _cy_

    _cy_ Long timer

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    nah... don't mind a bit ... me being a newbie to ADV and BMW both. but not new to going on cross country adventures.

    about 5 years ago I rode self contained on a bicycle from Bolder, Colo to Tulsa, OK on the Trans-American lower route.

    truth be known... I'm delighted that there is sooo much interest in bringing this R90S back to life. had zero clue that R90S is the most collectable of all BMW's from the 70's before I purchase the bike.

    may not be very knowledgeable about Airheads... yet... but I learn quick... especially when surrounded by sooo much expertise. don't think there is much that I cannot take care of with a bit of help of course.

    naturally I hope there is nothing wrong internally... but if there is ... I can take care of it. I'm fully set up with a machine shop and just about every type of tools imaginable. I'm a bonified tool nut.

    have always believed ... look at a man's tools and you can quickly tell what he's all about.

    [​IMG]
    #54
  15. supershaft

    supershaft because I can

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    Yea but I didn't see a leak down tester (differential compression gauge)? That's the gauge that helps!
    #55
  16. disston

    disston ShadeTreeExpert

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    I'm a bonified tool nut.

    have always believed ... look at a man's tools and you can quickly tell what he's all about.
    _______________________________

    Thanks for sharing. Very true. Nice accumulation or are you calling it a collection? Since you admit to being a tool nut, just wait till you see some of the special tools that you'll be craving. The BMW originals can be hard to come by. They are getting real collectable. There are quality modern versions and reasonably priced. One of the best sources and you'll be getting stuff here soon is Cycle Works. They have recently come out with a couple of things we have been needing for Airhead servicing. The have a new multi-tool to get into the timing case. It includes pullers that the equivalent generic type are pretty heavy and pretty expensive. And I was there today to get some wheel shims, I saw this new engine holding stand. Something that Airheads have not had access to for a long time.

    http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_51&products_id=379

    Or maybe I could make my own but I don't think it would be that nice.

    Charlie
    #56
  17. squish

    squish Out of the office.

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    What ever path you take with this bike is the right path.

    Sure polishing wheels and cleaning spokes is not high on some folks list. But it's a satisfying way to spend a few hours in the garage. It's not like the wheels will be worth less when you are done.

    One tip that I didn't see mentioned was to pull the oil pan, clean out the sludge and make sure the pick up is still firmly attached to the pick up feed tube.

    The also gives you a chance to see if there's any nasties lurking in the oil pan. All it costs is an hour and a new gasket.
    Assuming you don't strip a thread when you reassemble.
    #57
  18. _cy_

    _cy_ Long timer

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    thanks for the tip about dropping the pan. need to order pan gaskets first.
    would like to adjust the valves too. so need valve cover gaskets too.

    what's with BMW parts? no one discounts ... brake master cylinder costs $395 from all sources that I've able to find so far. looks like I'll be re-sleeving it instead

    here's the missing pic from above showing dial indicator from truing up front wheel.

    [​IMG]
    #58
  19. _cy_

    _cy_ Long timer

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    had a brain fart ...flat forgot I had a video scope ...

    all the comments about what if interior of motor is sound or not can be easily resolved by a Video scope. will be peeking inside soon.

    [​IMG]

    [​IMG]
    #59
  20. _cy_

    _cy_ Long timer

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    inside of tank is bone dry and clean. looks like tank was drained shortly after being put up. this bodes well. wouldn't surprise me a EE would have the foresight to take preventative measures knowing bike would be in deep freeze for a decade or more.

    all fuel lines are getting replaced. intake rubber hoses are going on parts list. yup, taking care of all the little things as I go along. sure like to go for a ride after the motor starts up.

    [​IMG]
    #60