Check yer brakes...

[Galaxieman]

So, long story short, even after upgrading the master cylinder on the front of the bike, a full-handed 4-finger brake 'clamp' (i.e. squeeze progressively until you can't squeeze any harder) wouldn't produce a front wheel skid, rear wheel lifting, or even a feeling of sufficient stopping power. A master cylinder designed to drive 4 pistons each on dual front brake calipers, or roughly ~4 times the fluid movement of the stock MC, couldn't produce enough force for me to even feel comfortable with the front brakes.

So I bought new pads and pulled the fronts to check...

GG-rated organic kevlar pads. Yep, that'll make a difference!

The new HH-rated sintered metal pads have a much better initial bite, and produce more force linearly with increased squeeze rate until the rear tire starts to float. Not quite the 1-finger stoppie power of some brake-upgraded CBR-RR bikes I've ridden, but definitely sufficient for 2-finger stoppies. From a riding perspective, it's one less variable that I have to worry about: No matter how good the road grip conditions, I will run out of traction between the tire and the street before I run out of brakes. Before, the brakes could overwhelm the tire in the rain, but not on dry pavement, which makes learning proper modulation for panic stops somewhat tricky.

The moral of the story is if something doesn't feel right, it probably isn't so you'd better double-check.

[Alex]

Yup! HH pads make a huge difference over organics.

[rojoracing53]

Moral of the story you need this

And this

[Galaxieman]

Um... yeah. That would be 'mildly over-spec'd...'. Brembo radial MC is pretty much bringing a rocket launcher to a gunfight. Is the caliper setup a kit, or something you made 1-off?

The stock rotor and caliper are actually pretty good, as long as you have decent pads. The stock MC felt squidgy, so that had to go though.

[80MPHdownhill]

Originally Posted by Galaxieman

A master cylinder designed to drive 4 pistons each on dual front brake calipers, or roughly ~4 times the fluid movement of the stock MC, couldn't produce enough force for me to even feel comfortable with the front brakes.

A larger master cylinder (i.e., one with a larger bore), designed for larger calipers, is ALWAYS going to require more hand force than a smaller bore caliper.

If you put a MC designed to drive 4 pistons each on dual front brake calipers, on a stock caliper Ninjette, it would require a tremendous amount of hand strength to duplicate the stock MC. It would make it very difficult to stop the bike quickly.

[Galaxieman]

Originally Posted by 80MPHdownhill

A larger master cylinder (i.e., one with a larger bore), designed for larger calipers, is ALWAYS going to require more hand force than a smaller bore caliper.

If you put a MC designed to drive 4 pistons each on dual front brake calipers, on a stock caliper Ninjette, it would require a tremendous amount of hand strength to duplicate the stock MC. It would make it very difficult to stop the bike quickly.

The differences in force are actually less than overall max squeeze hand strength, and you have the concept flipped. Given 2 calipers and a single master, if you delete one of those calipers, you will double the amount of pressure at the caliper for the same given input (squeeze distance at the lever; yes, I do realize it takes more force). If I put on a MC with a larger bore, I will get the same amount of force at the caliper(s) from less lever movement.

The lever movement piece is important because with the setup where it was when I started, I would squeeze the lever all the way to the bar and there wasn't nearly enough 'stop'. So, after upgrading the MC (larger bore, more fluid flow for same lever pull) the front end had more 'stop': I was able to apply more force because the lever hitting the bar was no longer the upper limit of braking pressure which could be applied. However, it still wasn't enough to lock up the wheel (except in the rain), so I knew something else was up. Swapping out for higher friction pads meant that for the same amount of pressure from the pad against the rotor, I was now getting MUCH more friction and more of that force being translated into 'STOP!'.

From a general usage perspective, I would imagine I would have had sufficient stopping power simply by swapping to the HH pads with the stock MC, but I had the spare MC and wasn't aware the pads were not up to par... so I did that first. Before I go racing I'll probably upgrade to a SS line, just so that any increase in fluid temperature from heavy usage won't do wonky things like make the line more pliable and the system more prone to fade. However, for street usage I'm really, really happy with the system as it sits now.

[rojoracing53]

Originally Posted by Galaxieman

Um... yeah. That would be 'mildly over-spec'd...'. Brembo radial MC is pretty much bringing a rocket launcher to a gunfight. Is the caliper setup a kit, or something you made 1-off?

The stock rotor and caliper are actually pretty good, as long as you have decent pads. The stock MC felt squidgy, so that had to go though.

No this is not a kit, its all a one off project of mine made from odds a d ends I have left over from my old racing bikes. Waiting right now for my Brembo full floating rotor buttons and a 15RCS master cylinder to arrive via mail tomorrow. I feel like a kid on Christmas Eve

[rojoracing53]

It's a simple matter of leverage but people will throw in the word power and confuse the **** out of every one. More leverage(smaller master cylinder piston)is more leverage so its easier to get more pressure(power) at the caliper but the lever will have more movement(feels squishy). Now a larger master piston gives you less leverage so less pressure at the caliper for the same lever pressure as before. This will give the lever a very solid feel very little squish(we like this) but with lower pressure at the caliper your pads won't feel like they're gripping.

So it's a balancing act and there is no right answer only one riders preference vs another riders preference. This is exactly why Brembo makes there racing masters in 6 different sizes.

[Galaxieman]

Did some quick checking, and as best I can find the stock MC is 12.7 or 13mm, and the Superhawk is a 14mm piston. This gives (at most) a 10.2% increase in required pressure (at the piston) to maintain the same force at the caliper. The larger issue is that the new MC produces a firm lever feel before the lever bottoms out on the bar, which the stocker didn't do. I've found it's easier to modulate brakes that have less lever sweep because (at least to me) the increase in pressure at the bar feels more linearly linked with the amount of increase in 'STOP'.

That said, as I was looking for the piston size info I ran across another thread on this forum where the rider didn't like the lever to be so stiff ("wooden" as the poster put it), so he was looking to go down in piston size. Definitely a personal preference thing, but my original point still stands: Check the damn pads. A previous owner had installed the GG pads up front, which was compounding my lever feel issues. Cheapest and least involved option (after bleeding the brakes to make sure air isn't the issue) is to pull the pads and check them...

[rojoracing53]

Back on topic "check your pads"

[Galaxieman]

Houston, I think we have a problem...

Incidentally, I sold my '02 Superhawk last year with just over 43,000 miles on it, and it still had 1/2 of the life left in the stock-from-the-damn-factory rear brake pads. I didn't really use the rear brakes too much

[Alex]

Originally Posted by rojoracing53

Back on topic "check your pads"

If you change them before you hit metal, you're wasting pads, right?

[rojoracing53]

Originally Posted by Alex

If you change them before you hit metal, you're wasting pads, right?

That's what I was thinking but I figured since my tire looked like this



I figured it'd be convenient to change both

[old3]

A 12.5-13mm master is the quick, dirty match for a 4 pot cal in supermoto. I'm about to fab a bracket to bolt up a 4 piston Tokico GSXR caliper and expect the stock master to be a great match.

I've dealt with "dead" or wooden lever feel when I deleted a caliper off the front of a KTM Adv 950. It worked but brake feel was awful.

[rojoracing53]

Originally Posted by old3

A 12.5-13mm master is the quick, dirty match for a 4 pot cal in supermoto. I'm about to fab a bracket to bolt up a 4 piston Tokico GSXR caliper and expect the stock master to be a great match.

I've dealt with "dead" or wooden lever feel when I deleted a caliper off the front of a KTM Adv 950. It worked but brake feel was awful.

I think you'll find the OEM ninja MC has to much leverage for a 4 pot caliper and will feel to progressive. But let us know what you think of the results, more info will always help in future endevors.

Is the GSXR caliper your mounting axel or radial mounted. I was originally going to use an axel mounted 2001 R6 caliper but after thinking a bit the current Radial mounted calipers would look much cleaner so that's what I went with.

[old3]

Convetional mount, non radial off a 2002 GSXR 750, same as the 600 I think. I'll post up a review of it, it has to be better than the stocker, I'm at the end of its usefullness with good pads and SS line.

[old3]

This is what I ended up with. A marked improvement over the stock caliper with SS line and EBC HH pads. It used to fade towards the end of a long stop, pull harder but get less effect. This has super feel and modulation, the power stays right to a dead stop too. I bet a mm or two bigger master might be even better but as is it is a true 2 finger brake.

It got a coat of black paint for now, blends right in. I figured the few other aluminum bits have cheap black paint anyway, looks decent enough.

[rojoracing53]

Originally Posted by old3

This is what I ended up with. A marked improvement over the stock caliper with SS line and EBC HH pads. It used to fade towards the end of a long stop, pull harder but get less effect. This has super feel and modulation, the power stays right to a dead stop too. I bet a mm or two bigger master might be even better but as is it is a true 2 finger brake.

It got a coat of black paint for now, blends right in. I figured the few other aluminum bits have cheap black paint anyway, looks decent enough.

Looks good

Are you still using the stock master cylinder? If so when you get a bigger MC don't go over a 15mm piston for radial pull or else you'll lose your leverage and the lever will be to hard to pull. Ask me how I know

[alex.s]

Originally Posted by rojoracing53

That's what I was thinking but I figured since my tire looked like this



I figured it'd be convenient to change both

lol. such a showoff

[old3]

Originally Posted by rojoracing53

Looks good

Are you still using the stock master cylinder? If so when you get a bigger MC don't go over a 15mm piston for radial pull or else you'll lose your leverage and the lever will be to hard to pull. Ask me how I know

I was looking at this, cheap and 14mm.

http://www.ebay.com/itm/BRAND-NEW-14...sories&vxp=mtr

[rojoracing53]

Originally Posted by old3

I was looking at this, cheap and 14mm.

http://www.ebay.com/itm/BRAND-NEW-14...sories&vxp=mtr

That's not radial and I think pistons size performance varies between radial & non radial. If your going to go non radial 14mm then I'd like to know what our stock on is so I knew I was going up in size but not to much. If that's off a bike that uses a "single 4pot" caliper then I'd gamble on it working just fine.

[old3]

I'm told it is 12.5, 12.7 tops. Anyone know for sure?

[old3]

The bottom of my master has t 2 2 c 19 cast in the bottom. It can't be a 19mm master, can it?

[old3]

I think I got it, there is a 1/2 on there too, meaning 1/2". Ah-ha!

So, a 14mm is slightly bigger, might be just the ticket.