The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Adrian on April 01, 2017, 01:46:19 AM
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Hi again - as I begin the rebuild of the old girl - I am thinking about a twin disc conversion. I'm having the motor converted to an 860 as the barrels are completely shot.
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So while the bike is still in pieces - and I have the money - it seems like a good idea to upgrade the brakes too.
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So does anyone know of a kit that I can buy to achieve this? I remember seeing one somewhere once before but I can't find it again.
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Thanks for your help .......
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BMW used to sell kits to do that, but they are no longer listed anywhere I can find them. You have a two stage problem - the first part is to find a matching caliper and the second is a master cylinder.
The best way to buy Brembo F08 calipers would be to buy a pair from somewhere like desmo heaven, remembering that what they call a "left" caliper" will be out "right" and vice versa. The size master cylinder you buy will be dependant on what size bores are in the F08s you buy = 36,38 or 40mm.
The last problem is plumbing, you have options - a short hose from master cylinder to splitter (if you don't have one they are readily available), or you may choose to run a single long hose to one of the calipers and then remove that caliper's bleeder and run a short hose to the second caliper (I don't like this method as i think it is visually unappealing).
other alternatives are:-
Buy a set of F08s from an early model K series and then machine the mounting "ears" so that the calipers centre over the disc. Noting that the work involved in this you may as well buy 4 spot calipers and machine them to fit.
Disc wise I am not able to locate anyone still making Cast Iron rotor replacements so you will be buying new Grimecia/Brembo ones form Motobins or Boxer works - taking a deep breath for Speigler.
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Out of curiosity, are you going to leave the gearing the same? With the extra power from the 860 kit you could fit a 32:10 or even 32:11 final drive (at the cost of having to mentally adjust the indicated speed on the speedo unless you want to go GPS speedo).
Which 860 kit did you buy?
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Here's a page from RealOEM.com, it shows what parts you'll need to source to do the twin disc upgrade .
http://www.realoem.com/bmw/enUS/showparts?id=0364-USA-09-1980-248-BMW-R65&diagId=34_0598
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Hi again - thanks Bob and Tony for the info.
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I shall chat with the owners of the engineering company that are specialists in BMW and who are fixing up the motor. The son - who works there - converted his R65 to an 860 café racer with twin discs. So he should be able to help me find what I need for the disc conversion.
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As to what 860 kit is being used - I have left it to them as the kit used by the son has worked well for him for a few years.
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I shall stick with the original gearing/rear drive shaft as I'm not bothered by extra speed but will welcome the extra power for carrying two people. I will change the main jets as - once again - the son has done this successfully with his bike. Tried and tested ideas are the best I find.
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In the meantime the rebuild continues - finally got the forks together today - after a bit of rotary sanding of the top clamp insert areas. Just the tiniest amount off made all the difference.
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Thanks again ........