[Jetcrazy14]

So I'm tired of my mushy front brake lever. Bike stops ok, there's just too much lever travel for my taste. Especially after riding my dad's 929 and feeling how nice, firm, and immediate those brakes were. So after looking at this thread and this chart I've still got some questions.

I currently have a 5/8 MC. My bike has 2 floating calipers, with 2 pistons each, with a 30mm diameter. So I'm sitting at a 14.28:1 ratio, a 16mm MC would put me at 14.06. Looking at the numbers this doesn't seem like it would be much of a difference, but 11/16 MC would be too much and the feel would be too "wooden."

So is a change of 0.22:1 going to make a noticeable difference in lever feel/travel or would I be wasting my money on a 16mm MC?

 

[Fight Everything]

I myself have little knowledge about upgrades in the master, but stainless lines help take the mush out. So does fresh fluid.

 

[Jetcrazy14]

I forgot to mention, it has fresh fluid. I flushed/bled back in March when I reassembled the bike and then just did it again a few days ago to make sure I had all the air out. I also already have stainless lines installed.

 

[Problomatic]

Swapped to sintered brake pads yet?

From what I READ just changing master cylinder or calipers isn't the way to go; if you're going swap components you need to do both. This was a really long, detailed article; involving lots of numbers and ratios and shit that basically said...something that I don't remember. But if you find the article, its a good one.

 

[Jetcrazy14]

Still running the stock pads. I was planning on doing EBC HH pads along with the master cylinder swap. The lever gets eventually gets good and firm, it just takes almost half the lever travel to do so and I'm wanting to lessen that wasted distance.
Then again, I'm losing mechanical advantage. Maybe I'll just do the pads for now to increase stopping power and then go from there wether I feel like I need to change the feel in the lever at all.

 

[shinyribs]

I swapped to full sintered pads on my 76 CB750. I hated them. Super hard pads that squealed real bad. And early CB's are bad about brake squeal anyway. My biggest complaint with my sintered pads (EBC HH pads) was that they felt dead when they were cold. Every time i pulled the lever it seemed like it was a moment before they really caught. I am assuming it was a delay thing due to cold pads since they did fine if you got on them at speed(80+ mph).

I set my bike up according to that chart once and I came away with mushy brakes. So mushy i refused to leave the house with them. I stepped up a size on MC bore (what the chart said would be wooden) and I love them. Lever effort is not extreme nor lacks modulation. Just a nice crisp,immediate feel to it. YMMV

FWIW, my brakes are two 42mm piston driven by a 5/8'' Nissin off a ZX600. My previous MC was 14mm stock to a CB750. Not a huge difference is bore size,but some of the feel has to do with piston travel inside the MC itself pumping more volume of fluid down the line.Something that the chart can't account for.
^^^ These are crap calipers on crap rotors on a 480lb bike.110-90/19 tire.It'll loft the rear tire with organic pads and my fat azz on there. I'm just not a big fan of sintereds JMO. I'd spend your money on a different MC rather than double H pads. :twocents: You're never gonna be happy with you lever feel regardless of pad material.

Good luck,hope you find a combo that works for you.

 

[MikeGyver]

New pads won't change the lever travel. Are you sure you got all of the air out? I've never ridden a Ninja 650, but my SV650 has the cheesy 2 piston sliding calipers and I don't have much lever travel. How much travel are we talking about?

 

[a_morti]

Hello matey, Morti here (OP of the thread you linked).

Your ratio as it is comes out to 14.24, which is already a pretty stiff lever. For conparison a '97 CBR900 comes out at 16.62, a GSXR750K2 at 16.27, a '98 CBR900 at 17.25, all more or less the same and significantly softer than yours.

I think actually if you go the other way and fit a 14mm master cylinder you will find you have more power in the lever, and will be happier with the brake. It comes out to 18.37 but so what, it's more powerful and will work stronger, and it's still much firmer than say the 955i speed triple or 600SRAD (both 20.98) both universally rated as having great brakes by riders and the biking press.

Remember, it makes Fuck all difference how much you can squish the lever while you stand next to the bike in the parking lot. It means nothing, as at this point you will have already locked the wheel and be skidding on your ass. This flex will also be more on floating than on fixed calipers anyway due to the extra flex in the calipers.

Start by doing a complete strip, clean, rebuild of your calipers, replacing seals if needed. Then gravity bleed them, for 100% air free lines. Then if this doesn't help, try actually going smaller on the brake master cylinder, not bigger.

If the 14mm is too much for you to stomach (and it'd just be pride stopping you trying it), Brembo make a 15mm master cylinder too. They can be bought surprisingly cheap brand new: http://www.yoyodyneti.com/ProductInfo.aspx?productid=10.4620.67 Although you cannot directly compare brembo and nissin master cylinders, this comes out at 16.00, which is slightly firmer than sportsbikes from when they still have axial brakes.

Or, do a better job and fit fixed calipers and matching master cylinder, probably the 5/8" you have would work. Maybe change the forks if you have to.

 

[a_morti]

I swapped to full sintered pads on my 76 CB750. I hated them. Super hard pads that squealed real bad. And early CB's are bad about brake squeal anyway. My biggest complaint with my sintered pads (EBC HH pads) was that they felt dead when they were cold. Every time i pulled the lever it seemed like it was a moment before they really caught. I am assuming it was a delay thing due to cold pads since they did fine if you got on them at speed(80+ mph).

I set my bike up according to that chart once and I came away with mushy brakes. So mushy i refused to leave the house with them. I stepped up a size on MC bore (what the chart said would be wooden) and I love them. Lever effort is not extreme nor lacks modulation. Just a nice crisp,immediate feel to it. YMMV

FWIW, my brakes are two 42mm piston driven by a 5/8'' Nissin off a ZX600. My previous MC was 14mm stock to a CB750. Not a huge difference is bore size,but some of the feel has to do with piston travel inside the MC itself pumping more volume of fluid down the line.Something that the chart can't account for.
^^^ These are crap calipers on crap rotors on a 480lb bike.110-90/19 tire.It'll loft the rear tire with organic pads and my fat azz on there. I'm just not a big fan of sintereds JMO. I'd spend your money on a different MC rather than double H pads. :twocents: You're never gonna be happy with you lever feel regardless of pad material.

Good luck,hope you find a combo that works for you.

On this setup your options were 14 or 18, when ideal is about 16. So it turns out you prefer a bit "too" firm, compared to a bit too mushy. Nicely brings up the point that there is personal taste to account for. If you do ever feel the lever is a bit hard to pull, consider that 15 linked above, comes out pretty near to the "perfect" ratio of 16.

I still put the usable range on dual calipers between @14 to @18 myself, I wouldn't want to go lower than 14. Maybe that's my personal taste talking, but I submit I've messed about with enough brake systems to be able to make some useful comparisons of what at least works well.

Another thing to consider - I don't have an especially strong grip, so for me a smaller master cylinder is good. If you happen to be a blacksmith, you might find a bigger one feels better. And so on...

 

[a_morti]

Still running the stock pads. I was planning on doing EBC HH pads along with the master cylinder swap. The lever gets eventually gets good and firm, it just takes almost half the lever travel to do so and I'm wanting to lessen that wasted distance.
Then again, I'm losing mechanical advantage. Maybe I'll just do the pads for now to increase stopping power and then go from there wether I feel like I need to change the feel in the lever at all.

EBC pads are not good, leave 'em alone, or you'll need new discs sooner than you'd want to. Stay with stock for the best compromise of cold/wet/dry performance without chewing up your discs. Or if you must, then consider HH pads, but only if you (be honest now) really ride hard enough to keep the brakes hot all the time. It's a similar compromise to using soft race tyres on the road - for most riders in most cases it's worse grip as they aren't kept hot enough to work right.

The extra play in the lever is likely to be either just down to sliding caliper design, or if you have extra play in the floating pins this would definitely contribute also. Also if even one piston is sticking, even partially, this will also contribute. Hence the suggestion of a decent caliper clean up.

 

[Jetcrazy14]

Awesome! Thank you! That is the type of response I was looking for with this thread as I'm pretty new to this whole thing. I tried some heavy braking today and was able to lift the rear wheel with this stock setup (except the SS lines) and also realized exactly what you were saying with the squeezing in the lot vs. actually riding. Thank you everyone else as well.