This has been done and discussed ad nauseum but as I'm playing again, thought it might be useful to open a thread.
As I see it there are several options for improving the braking power to the front. These options overlap with those which will increase brake endurance. I am more interested in increased braking power as have not encountered the need for more endurance as could be needed during mountain touring and the like.
In order to increase braking power, one might improve:
1) Increasing pad/rotor area.
2) Increasing rotor radius/diameter, which may correspond with #1.
3) Increasing pad frictional coefficient.
4) Increasing hydraulic pressure
#1 has been done and is well documented with upgrading of Gen1 to Gen2 caliper & rotor (marginal) or upgrading of both to 320 mm rotor.
Adding another model of dual piston caliper has also been accomplished but less often than for the 320mm rotor alone.
#3 is well reported.
#4 is the area which interests me the most at this time, although most efforts in this area have been going in what seems the opposite direction.
A friend emailed regarding a discussion of this subject area on another group to which I do not post so thought it worth while here.
There have been many reports of improved braking through the installation of improved brake hoses which expand less due to pressure. These will improve braking if:
1) The "give" in the hydraulic system preserves some lever stroke which can apply additional pressure to the caliper. This will generally be the case only when the lever is otherwise clamped to the grip by hand pressure.
2) The "give" in the hydraulic system moves the the lever to a more ergonomic position allowing the grip to apply more clamping force.
I am aware of some instances in which the more ridged hoses have resulted in poorer braking because the lever was working in a less advantageous arc.
There have been many reports of improved braking through the installation of ( usually from dual caliper applications) larger diameter master cylinders however there has been little speculation and even less investigation as to why this might be effective. The obvious question is: how does a larger piston diameter, which must result in lower hydraulic pressure, result in better braking. There are too many reliable reports to dismiss the claim.
Even the possibility of better lever arc would seem less likely, given the number of positive reports. I speculate that the reason may be better (greater) lever advantage?
I do note that we have improved the braking of many KLR's by simply cleaning and lubricating the lever pivot bolt and lever tip. I hope that no one overlooks this possibility.
I've just ordered a Ninja 250 master cylinder to try as the bore is 10 mm versus the KLR's 12 mm.
Some reports of improvement have included 14 mm bore master cylinders.
Please check my calculations as am distracted by the extra time 1:1 Greece- Costa Rica game.
I calculate as compared to the stock 12 mm bore:
10 mm has 69% of the area, resulting in 145% of hydraulic pressure
14 mm has 136% of the area, resulting in 73.5% of hydraulic pressure
In this event, assuming sufficient apply volume, the 10 mm master cylinder should produce markedly increased (145%) clamping force at the caliper.