Although I'm a stickler for originality when it comes to my '75 R90/6, I have finally decided to do a bar-mounted master cylinder. I'm going with the 12mm unit, part number 32722302367, but it appears to be built for just one throttle cable while the /6 has 2. Is it simply a matter of swapping the cover to accommodate the second cable? (I have the later, squarish cover and the larger diameter, 2-cable 33 throttle cam disc). Thanks.