Bringing 74 R90S back to life after sitting 30 years

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

  1. WU7X

    WU7X The Old Fart

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    Congrats! It really is a beauty!
  2. _cy_

    _cy_ Long timer

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    first little outing to Pawhuska Ok from Tulsa ... about 120 miles round trip

    just outside of Barnstall, OK .. home town of Clark Gable
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  3. Xcuvator

    Xcuvator Justa Venturer

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    Nice looking bike and weather. Did you spend a week there?
  4. _cy_

    _cy_ Long timer

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    testing Aerostich Roadcrafter for water worthiness. a bit unfair since I scrubbed suit hard with soapy water before dousing with a full stream of water. results after 15min of scrubbing and dousing with water... soaked inside.

    will try water only next time

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  5. Wirespokes

    Wirespokes Beemerholics Anonymous

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    You're supposed to waterproof the suit every now and then. Sounds like it's time! :wink:
  6. Airhead Wrangler

    Airhead Wrangler Long timer

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    No matter how well you waterproof them aerostich + rain = soggy crotch (eventually legs too)
  7. fishkens

    fishkens Long timer

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    +1 The zippers simply aren't waterproof. The suit could be more waterproof but that would compromise the easy entry/exit, although I do believe they're now using more water resistant zippers seen on mountaineering gear.

    From their site:

    Waterproofing Zippers?

    The Roadcrafter’s unique zipper arrangement can become a source of water entry in extremely wet conditions. To dramatically improve performance in severe conditions use either a wash-in water repellent or hand seal these areas: 1) Stitching and knit zipper fabric around both underarm zips; 2.) The knit zipper fabric along the right leg zipper; 3.) The stitching and knit zipper fabric along the left leg zipper from two inches above the bottom of the Velcro flap, to below the knee.
    Wash-in repellents like Nikwax TX Direct® penetrate everywhere during laundering. In addition to improving breathability in wet conditions, they minimize leaks around zippers. Seam sealing products like Seam Grip®, should be thinned enough to completely soak into the fabric, thread, and stitching. (Use Cotol® or toulene.) Apply sealant to both the knit zipper fabric and the stitching.
  8. sdpc2

    sdpc2 Just another Rally Rat

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    Greg is known for having some really nice G/S's over the years.... and i've never even met the man. But i seriously considered buying a bike from him a few years ago...
  9. _cy_

    _cy_ Long timer

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    G/S in front of Frank Loyd Wright Price Tower yesterday
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  10. _cy_

    _cy_ Long timer

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    Leaky Bing carb fix on R80 G/S ... tried everything else without success.
    it was time to replace the seat. removing seat by carefully following below method requires no heat.

    use a 24 - 5/16 tap then screw same pitch bolt into now threaded brass seat.
    use a nut with ID larger than seat for a spacer. then simply turn nut to pull out.

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    easy does it when making initial pull. taking apart several times to inspect pull is coming out straight.

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    use a brass drift to gently tap new seat in

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    correct float height setting. float level with edge of bowl.

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  11. disston

    disston ShadeTreeExpert

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    Thanks Cy,

    That's the first time I've seen this explained so clearly and with pictures. Nice operation.

    It is pretty amazing they can leak I think and not show any deformity. Was that also your experience?
  12. _cy_

    _cy_ Long timer

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    yes... tried everything multiple times ... changed out to new floats, new needle, tried different float heights, new float bowl gasket, etc.

    it'd hold for awhile like overnight, then start leaking again ... it was time for a new seat
  13. Duckmeister

    Duckmeister midlife crisis@64

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    I too am bringing back to life a 74 S model. In the event that you need to resto the guages,I can recommend Terry Vrla in Oregon. He goes by "Wirespokes" on this site. Great job,very fair price. Best of luck with your Beemer...
  14. _cy_

    _cy_ Long timer

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    working electronic ignition yanked on R80 G/S

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    these little lovelies are in it's new home (one spare beancan with points)
    fired right up with static timing ... double check with timing light tomorrow.

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  15. chasbmw

    chasbmw Long timer

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    This looks like a very early 90/s with the solid discs, if it is likely that the calipers are 38MM (if they are not marked with a 40, then they are 38s).
    My dual 38s work very well with a 13mm handlebar master cylinder, so i suggest the smaller the better if you want more poweful and responsive brakes.

    Charles
  16. chasbmw

    chasbmw Long timer

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    with an early R90S like yours it is worth running an earth wire from the front indicators back into one of the earths in the headlamp.
  17. nobbylon

    nobbylon Been here awhile

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    I happened upon this thread the other day and have really enjoyed reading through it. Great to see another r90s back on the road. I fell in love with these bikes aged 12 in 1976 when my Dad used to take me to Sports motorcycles showroom which was on Liverpool rd in Manchester UK. It used to be my brother and my treat for the weekends! I can still smell that showroom full of '76 BM's. The window display was a daytona orange r90s and I still have a picture of it with my brother in the background.
    After a succesion of bikes starting with a '78 r100s and going through various japanese sports bikes I eventually realised my dream and bought a '75 daytona orange r90s nearly 14 years ago. I commuted on it weekly for 5 years and then circumstance changed and it now sits in my garage most of the time.
    It's had a fair share of work done including frame painting, unleaded ported and twin plugged heads, magnacor, boyer ignition, stainless pipes, konis at rear and american progressive springs with modified damper rods at the front, upper billet triple clamp and a lower fork brace. The wheels were respoked by a chap called Keith Berry from Bolton using the original rims and stainless. After reading this thread I fired her up at the weekend and went for a blast. It never fails to leave me grinning ear to ear.
    Thank you for posting all the pics and stories and also for getting another of these amazing machines back into running order,
    john (Nederlands)
  18. _cy_

    _cy_ Long timer

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    welcome to ADV nobbylon .... stick around some of the most knowledgeable Airhead guru's (not me) hang out on ADV.
  19. gasolinePony

    gasolinePony Adventurer

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    I have a R75/6, and in the midst of trying to figure out why my front wheel won't roll, I'm seeing very much what you've got depicted here. Rusty, and ugly under the MC. I have a few questions for you if you don't mind (I'm a noob :bow) . What is the "bore" you are inspecting, and I saw the solution that you made out of your own construction of the bottom gasket--is that still what you would recommend? I'll consider a handlebar mounted mc, but wanted to get your final say after all the hard work!
  20. _cy_

    _cy_ Long timer

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    hey I was a noob too when this R90S project got started.

    lots of folks prefer new master cylinder route. but really wanted to keep R90S stock. your mileage may veri...

    reason mine was locking up, brake hoses were collapsed internally not allowing fluid to retract. allowing brake fluid to move one direction only. if unscrewing brake hose releases pressure, freeing up caliper. you've got a positive indicator hoses are bad. if wheel is still locked up after releasing pressure. you've got frozen calipers.

    if you decide to rebuild master cylinder. measure bore diameter and inspect bore for deep pits, before you order BMC kit. unfortunately could not find anyone to supply reservoir O-ring.

    be sure to only use O-rings made from brake fluid resistant rubber. part numbers are provided in earlier posts.

    if master cylinder worked properly at one time, it can be make to work again. fix your BMC and replace your brake hoses. before moving on to your caliper. fortunately calipers rubber go bad much less often than BMC.