2. "My brakes really suck; what can I do to improve their performance?Add-ons?"
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This article is from the Ducatis Motorcycles FAQ, by Duke Robillard duke@io.com with numerous contributions by others.
2. "My brakes really suck; what can I do to improve their performance?Add-ons?"
(Thanks to Michael Nelson, nelson@seahunt.imat.com, and Julian Bond,
julian@shockwav.demon.co.uk, for help on this one.)
Before you contemplate investing serious money in add-ons that may or may
not make that much of a difference, start with the basics first; they're
less expensive (usually) and can make all the difference in the world. The
items you can try below assumes there aren't more serious maintenance
issues like deteriorated seals, minor rust in the master cylinder or just
plain crap in the lever pivot.
1) First, just bleed 'em and replace the fluid with some good DOT 4 stuff.
Flush 'em out real good, and clean the dust and crap out of the caliper(s).
Make sure when you bleed them that you get ALL the air out; often a bubble
will get caught in fittings and in the "L" junction where it goes into the
master cylinder. Removing the master cylinder from the bars and tapping on
it with something like a plastic screwdriver handle while bleeding them
will often dislodge such bubbles.
Bubbles often get caught at the junction with the M/C. One way to clear
them is to go through the normal bleeding procedure and then bleed the
brakes from the bottom up. You can do this by leaning the bike on its
sidestand with the forks hard left. This gets the reservoir to the top of
the system. Then gently pull the pads back, this forces fluid up the lines
taking the bubbles with it. You can actually do this with the calipers in
position with a mole wrench but use a bit of cloth over the caliper so you
don't mark it. Its really easy to squirt fluid everywhere from the
reservoir so don't fill it too full and put the cover on first.
Some people have had success leaving the bike overnight with a bungee cord
round the brake lever which also seems to persuade the bubbles to move.
2) While you're at it, get some fine emery paper and lightly sand the
rotor(s). The key word is LIGHTLY. You don't want to sand in some low
spots; just get the glaze off of them. Make sure they aren't warped by
inspecting them laid down on a perfectly flat surface, and that they are
within the proper limits for thickness. Better yet, have someone make the
inspection for you -- how many folks actually have something that's
perfectly flat?
3) Check the pads. Make sure they aren't glazed, and if you didn't break
them in properly (see Paul Thompson's excellent piece on breaking in new
pads, included in this FAQ) put new ones in and break THEM in properly.
4) Lube the lever pivot points to make sure everything is moving freely.
If, after all of the above, the lever still feels mushy, it could be a good
excuse to ante up some money and swap your rubber brake lines for braided,
stainless ones.
It seems that the stock Brembo pads aren't very good at dissipating heat.
When they get hot, they get the brake fluid hot. When the brake fluid gets
hot, the lines can get warm and spongy feeling. This can manifest itself as
FADE. Riders have reported that the lever can, in fact, come all the way
back to the bars over extended hard uses when the fluid temps get elevated.
This is bad. Try different brands of pads -- EBC, Ferodo, SBS all make pads
for the Brembo calipers.
The absolute last thing to try would be either replacing the rotors with
cast iron ones, or replacing the master cylinder with a larger one. This is
a last resort, and not for the weak of wallet. Definitely try all the other
stuff first -- a complete set of lines including two for the front brake
rotors, one for the rear and one for the clutch runs about $150 as of this
writing, not counting installation. Opt for Kevlar if you can afford it.
If you've done all that and you've still got mushy brakes that drive you
crazy, you can put on a racing Brembo or AP Master Cylinder, or a Nissin
Master Cylinder, like the one from the Kawasaki ZX-7R. I hear this is
actually the setup Doug Polen used in 1993 to win the World Superbike
Championship on the 888.
The reason this works is likely because the Nissan master cyclinder has a
larger piston (5/8") than the stock Brembo. Word is that up to '97 (98?)
almost all Ducatis have had a M/C with too small a bore. The larger bore
means the lever harder to pull, but it flows more hydralic fluid, which
moves the calipers faster. Consequently, the lever doesn't need to move as
much, which eliminates what we call "sponginess" and prevents the lever
from coming all the way to the bar.
People have successfully used the master cylinder from the 1992 ZX-7R (not
the ZX-7, but the ZX-7R, the race replica version), and from a 1994 ZX-7. I
also heard that all the ZX-7 master cylinders with remote reservoirs are
the same between 1992 and 1995, which seems likely. I even got a part
number: 43015-1392.
The reservoir should be < $85 used. Two guys bought new ones from Crazy
Caton's (a mail order parts place, 800-745-BIKE) for $135. Someone else
used East Coast Warehouse (800-544-4814) and it came to $145, including the
banjo bolt (see below).
This has been done on 888's, 916's and 900ss's. Someone also put a ZX6
master cylinder on a Monster. I've come to suspect that any good Japanese
master cylinder would work on any Duc, but those are the ones I got reports
on.
You need a new banjo bolt; the one on the Duc's Brembo master cylinder
doesn't fit the Nissan. (The banjo bolt is the funky bolt that connects the
brake lines to the master cylinder. It's hollow, and brake fluid flows
through it). Lockhart Phillips has cool ones with a built-in bleeders for
about $20. You also need a new brake lever; the Brembo lever doesn't fit.
You need to come up with a support for the remote reservoir; it doesn't
come with one. People have done a number of things: used the support from a
CBR900RR, adapted the Duc support, fabricated something, or re-used the
remote reservoir from the Brembo system with the new Nissan caliper.
The actual work of replacing the cyclinder is pretty straightforward: take
off all your body work (brake fluid eats paint, and you'll spill some),
drain the Brembo, take it off, put the other one on, and bleed it 8 or 10
times. :-> On 916's, there's a little locating pin on the handlebar to
position the cylinder, and keep it from rotating. A cavity in the ZX7
cylinder fits over the pin, but not firmly. One guy filled the cavity with
expoxy to get a good fit.
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