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Thread: 1984 R65 Brembo Brake Identification (36mm bore?)

  1. #1
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    1984 R65 Brembo Brake Identification (36mm bore?)

    So on my '84 R65 - I would like to rebuild my front brake caliper & master cylinder, as the front brake has always felt weak to me. Right now, I'm trying to identify my front calipers.

    I have a single Brembo caliper on my bike, mounted on the left as shown in the picture. Looking at the back of the caliper, it's stamped 7A-36. I'm assuming that means the bore is 36mm? From what I can gather, the Brembo calipers for this model should be 38mm.

    I would appreciate any help with identifying what brakes I have - I've come to find that my bike is a bit of a Frankenstein, so I wouldn't be surprised if the calipers are not original.
    Attached Images Attached Images

  2. #2
    Registered User STEVENRANKIN's Avatar
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    While you are at it

    Sorry, I can't help you with your question but I will stick my nose in and give a bit of advice while you have things apart. Replace the brake lines. Over time the original lines break down and get soft leading to a mushy feel when braking.

    Best improvement is to change to a stainless brake line of some sort. There are many different brands on the market but buying from EME, Boxer Two Valve or some well known supplier of BMW performance parts will get you a good deal.

    Good luck on the rest of the rebuild and again sorry I can't help.

    If you give the folks at Max BMW or EME a call, they will be very happy to get you the parts you need for a rebuild. St.

  3. #3
    And I'll add to the non-answers by recommending red rubber grease when you reinstall the pistons. It makes a very difficult job easy.
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  4. #4
    Registered User PAS's Avatar
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    Max BMW shows an ATE caliper on the 84 models. Make sure you do some more research.

  5. #5
    Registered User STEVENRANKIN's Avatar
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    Microfiche

    Max BMW's microfiche shows ATE and Brembo brakes for the 78 to 85 bikes.

    This is for left and right calipers O69 and 070. St.

  6. #6
    You could pull the caliper and measure the piston, preferably with vernier calipers.
    '13 690 Duke, '19 Ninja 400 (track bike), '21 Duke 890R, '22 Street Triple RS, '22 S1000XR (gone but not forgotten: '61 Clubman's Gold Star, '76 R75/6, '84 R100, '76 R90S, '20 R1250R)

  7. #7
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    I don't claim to know the specs for your set up, but that sure looks like a F05 Brembo body, right side would be a # 20.2676.40 RH Standard, which are only 2 X 32 MM. Rebuild parts are available. As others have stated, be sure to check what you really have as far as piston size is concerned.
    Dave Hutton '78 R100S (mfg 7/77), '06 Kawasaki Concours, '82 Suzuki GS1100G, '82 Yamaha Exciter 250, '73 TS125

  8. #8
    Quote Originally Posted by tatertoph View Post
    So on my '84 R65 -

    ... Looking at the back of the caliper, it's stamped 7A-36. I'm assuming that means the bore is 36mm? l.
    from my vantage point , this LOOKS like the identical caliper body casting as on the rear of my 78 R100, which is likely original.
    My casting is stamped 16E7 so the "casting # = diameter " theory may not hold fluid.

    My pucks are 38mm and both are way way more corroded than the fronts, probably due to the moist & unheated location of the reservoir ,
    as opposed to the under tank location up front which may keep everything drier. Or it was just a case of no good rotten dust shields.
    The pucks are pleasantly cheap @ ~$16 pair @ euro, and of course the need arose immediately after placing my next "last" order for this build.

    While the body bores show some scoring wear on the dry side of the square seal, its only the body bore INSIDE the seal that I'm slightly concerned about.
    The sealing is done by the square O ring riding on the steel puck, the alumium bores are just there to keep everything squared up , not a tight tolerance.
    As long as the wall does not hang up on the puck ( I'll run a brake hone in there before building ) I think I'm good to go , er, stop

    I blew out the pucks with compressed air as usual ,but the looser one pops out first of course, and with no seal/no puck on that side, the 2nd puck isnt going anywhere via same method. Separate the casting body in half to blow the more stuck one ... needed to clamp some plastic stock over the exposed port to keep the air pressure channeled into cavity. Then be sure to aim the puck side at the padded work table so it doesn't hit the sky or eye.

    It may have helped to remove the stuck puck after dosing inside w/ a little LiquidWrench and a blast w/ the heat gun the loosen it up, I'll never know but thats what I did
    Last edited by gtgt_bangbang; 09-22-2022 at 09:33 PM.

  9. #9
    Quote Originally Posted by tatertoph View Post
    single Brembo caliper on my bike... wouldn't be surprised if the calipers are not original.

    Mine needing pads & pins, pucks + seal kit plus clean up & paint, for me its a tough call to not just buy the whole thing new; pads loaded & shipped for ~$120

    auctions come and go but search term " Ducati Brembo P2 38mm F08 Right Front Rear Brake Caliper Bevel Darmah FO8" hits on a caliper that sure LOOKS like mine

    https://www.ebay.com/itm/33392019194...Bk9SR5b2qbTtYA

    from gotham on ebay.

    Rebuild is certainly not difficult but the parts alone are pushing 100 bucks

    Can any one here say if this Duc caliper isnt compatible with beemer ? Looks like a swap to me
    Last edited by gtgt_bangbang; 09-23-2022 at 06:29 PM.

  10. #10

    delay of game

    dont jump on those Duc / Brembo calipers as a swap for a Airhead rear caliper just yet

    the reply from vendor ( who does not take returns) indicates the Duc part may be a slightly smaller / look-alike version of the BMW caliper.

    verifiying that now with vendor , will relay results soon

  11. #11
    may have to try a vintage / universal fit

    brembo - 1.jpeg

  12. #12
    Quote Originally Posted by tatertoph View Post
    I'm trying to identify my Frankensteins ,

    looks a lot like this . can let you know in a couple days anything dimensional about it ...

    https://www.oppracing.com/product_di...lack-20355640/



    bmw R100S brembo f08 rear - 1 (1).jpeg

  13. #13
    Quote Originally Posted by tatertoph View Post
    So on my '84 R65 - I would like to rebuild my front brake caliper & master cylinder, as the front brake has always felt weak to me.
    ?
    I thought all 84 R65s came with dual front disks, and earlier models were single caliper. Back in the day some people “upgraded” their early R65s to dual disks to improve braking.

    Anyway, those single disk bikes were never known for sensitive brakes, especially compared to what we have now. The original pads were hard and wore like iron, and brakes often squeaked when applied. Your bike may still have original pads in the caliper.

    Rebuilding cylinders is not likely to result in stronger brakes, but a simple and easy change to better pads might. If your bike has them, make sure the sliding pins are not seized when you take the caliper loose. Seized pins can reduce braking a lot!

    Good luck with your project.
    -Live as fully as you can as long as you can-

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