First off good on you for keeping on a bike. A average person would give it up. As you go down this path, don't forget the is a leverage ratio at work and master cylinder piston travel at work. It has to do with the diameter of the master cylinder piston and the diameter of the slave (caliper) piston. Honda uses different piston diameters to bias the brake, adjust the lever-pedal pressure and adjust the feel. For example if the diameter of the master cylinder is 16mm the surface area of the master cylinder piston is 2.01 Sq. centimeters. If the diameter if the slave is 37 mm the surface area of the piston is 10.75 Sq. centimeter. This makes an effective ratio of 10.75/2.01 or about 5 to 1. If you add a second slave to the same master the total surface of the slave will be 10.75 x 2 = 21.5. The effective ratio will be about 10 to 1. This will make the brake feel a lot more spongy. The other issue is to move the double slave cylinder, the master piston will need to move twice as far for the slave to move an equal amount. On modern bikes with huge rotors and four to six pot calipers, the ratio is turned way down to give the brake a hard, powerful brake. I would measure the piston diameters, total up the surface area of the slaves and try to keep the ratios close to stock. Just my 2¢
OUTSTANDING. Thank you ... this gives me a way to calculate what will work rather than 'just trying stuff' and hoping it will work out ! Thank you James !
As it stands now:
The stock master cylinder was sized to activate the front single caliper only. It has had the Sidecar caliper plumbed in as well, and sure enough it feels spongy. I should be able to research the piston sizes of the calipers, and find an appropriate sized master cylinder to do the job ...
Maybe even find a master cylinder that can drive all three calipers (Both front calipers and sidecar caliper) so that I can
A. Stop in a timely fashion, a very desirable behavior.
B. Not experience the left hand veer on hard braking. I could live with this as a trade off for safety, but would rather have my cake and eat it too ...
Again , thank you for the info !