I’m sorry if those more committed to originality consider the following to be heresy, but I am told by those who know more about the marque than I do that my vandalism was as common back in the day as replacing the four into four pipes on a Z1 with four into ones.
It had the strange linked brake system and I am replacing it with the front M/C feeding the front calipers and the rear M/C to feed the rear as God intended
The owner has supplied me a master cylinder which I think will be the right size for both calipers, but I clearly need a small bore M/C for the rear. Can anyone recommend a suitable and readily available one for this job. I assume I will have to make up some bracketery but some pointers as to what others have done would make my life much easier. His original stock rear M/C was rotten so that wasn’t ever going to be an option anyway.
Firstly, you’re dead right that back in '77 onwards, LM owners did all sorts of things to make the machine more rideable. My take, is you do what you want to make it the machine you want to ride.
Delinking the brakes was one of the more common things to do back then, I heard about it all the time as a Jap 'bike rider. Principally it was because they just weren’t used to linked brakes, reacted, and just delinked them. When I bought mine in '91 I was all ready to do the same, because that’s what a lot of people did. But I rode it first and actually found that, even the primitive system on Mk1, was utterly brilliant and didn’t take much getting used to at all.
So, personally, I’d build it linked and try it out. You may find, particularly in the modern world where almost everything has linked brakes ( albeit seemingly off the front brake lever, these days ), that you like it.
However, if you’re determined to delink them, what everyone did back then, was simply reroute/make new hoses and use the original master cylinders. The effect was to make the front brake really quite fierce, but the lever had a bit more travel, because it’s a smaller diameter than normally used on twin discs, which at the time was amazing, but now just feels like a modern brake rather than the rather wooden Brembo feel. The back became less fierce because it now had more area than it would have had so less mechanical advantage, and that’s fine.
Of course, if you wanted to be flash, you could use your nice, new twin front disc master cylinder to operate the linked front and rear caliper off the handlebar and use the pedal to operate the other front disc, making it a bit more modern compatible.
