Been doing some "research" trying to get to the bottom of getting better braking out of a dual system off a master designed for one caliper.
I'm not positive my woes stem from a mismatch in the master to the 2 caliper volume, but really feel it's there. New brake pads may resolve some of it, but before i go that route i'm doing some "testing."
a buddy of mine gave me a master off a 250 quadracer, darn near identical to the yerf master C and I are using. externally, they're both basically the same. internally the bore is a 1/2 and the bore depth and stroke limit is the same length. so apples to apples, until you get to the piston. I'd been thinking about the fluid passage design of the piston and the width of the spacing. thought the yerf had narrower passages and maybe widening them would help. thoughts were actually backwards.
the yerf has a very wide spacing as shown.
springs were also the same size, but different rates, I put the softer one in.
after doing cleanup on the suzuki piston (the rod pocket end was snug in the bore), i installed it in the yerf master.
Along with the suzuki master, my friend also gave me one off a yamaha, think it's an old yz-125. bolt pattern is a mismatch, but that can be fixed.
What' i've found is that most name brand masters have the internal bore size cast on their sides. the yammer is a 14mm. it was in really bad shape, but managed to get it apart, clean it up and make it safely functional. depth and stroke are the same, so overall, it will push a 1 mm larger bore size of fluid per stroke. no i'm not doing the math!
this may be enough to get me what i need.
At this stage, I still need to refill/bleed the lines (at least i came up with a tried and true easy method)
I won't be able to test the "combo" master for awhile since i've torn down the front steering system to improve it.
My thoughts right now are that the piston difference may only affect the firmness of the stroke and most likely not move any more fluid. if this proves out, then the yamaha master goes in for a test.
Just wanted to start a thread on this so if anyone else goes down this road, they know what to expect.
C ... i've also found a couple other used masters on e-bay with 11/16ths and larger bore sizes with essentially the same mount pattern and line placement. key is to look for the inch or metric number cast on the side of the master. on on used quad brake assemblies sold as a whole, it's typically hidden by the plate it's mounted on.
piston -- yerf left, suzy right
master -- suzy left, yerf right