List of Bolt-On Front Brake Mods
VTR virgin
Superstock
Joined: Mar 2015
Posts: 447
From: Auckland, New Zealand
My 2 cents worth on the brake upgrade is that the stock VTR master cylinder/piston ratio is not ideal, and the later 4-piston calipers from things like the 929, 954, 600F4i and SP1/2 are better again.
Honda tried a few iterations of master cylinder diameter to caliper piston diameter ratio, and for my money I prefer the feel of the 30/32mm calipers (954 and SP2) with the 17.46mm master.
In my experience and opinion, the 600F4/929 set up errs with a too small master (15.87mm) for too big caliper pistons (32/34mm), making for a too-grabby brake.
The 954 set-up to me is the sweet spot for these brakes. FYI I have the 954 set on my VTR, and a 17.46mm CBR600RR master and 600F4i calipers on my VFR.
The joyful thing about all this is that you can mix and match to your hearts content and end up with a stock-appearing brake that is personalised to your tastes.
Honda tried a few iterations of master cylinder diameter to caliper piston diameter ratio, and for my money I prefer the feel of the 30/32mm calipers (954 and SP2) with the 17.46mm master.
In my experience and opinion, the 600F4/929 set up errs with a too small master (15.87mm) for too big caliper pistons (32/34mm), making for a too-grabby brake.
The 954 set-up to me is the sweet spot for these brakes. FYI I have the 954 set on my VTR, and a 17.46mm CBR600RR master and 600F4i calipers on my VFR.
The joyful thing about all this is that you can mix and match to your hearts content and end up with a stock-appearing brake that is personalised to your tastes.
Senior Member
Back Marker
Joined: Nov 2013
Posts: 171
From: Los Angeles, CA
Yeah and I'm a little confused as to how a truly sealed brake system full of fluid is continually "absorbing" moisture from the small amount of air trapped at the top of the system. A properly bled system only has a single source of air that it can exchange with, the bolus of air at the top and unless you run the thing dry, the piston part of the master cylinder will never see "air"
Over a long term fluid "degasification" can occur causing microbubbles to form in the line hence why zipties around the brake lever overnight can improve lever feel immensely on regular intervals because the pressure change of a pulled in lever over long term can help mitigate those bubbles to the top. In some of the more crazy chemistry we do, stirring / pressure is used to aid in degassing fluid.
Every glass of water you leave out a few days "degasses" even at rest and will form microbubbles within it, shaking the glass or stirring the liquid breaks these up
I work regularly with hydraulic fluid and line length + proper bleeding + no air in the system is ESSENTIAL for properly aligning two huge pistons that lift the top of my several ton particle accelerator "lid". Any air bubbles will cause the pistons to move out of relation to each other causing a jam because the piston on each side won't be in sync. Our brake systems are much simpler
My 3 cents
Over a long term fluid "degasification" can occur causing microbubbles to form in the line hence why zipties around the brake lever overnight can improve lever feel immensely on regular intervals because the pressure change of a pulled in lever over long term can help mitigate those bubbles to the top. In some of the more crazy chemistry we do, stirring / pressure is used to aid in degassing fluid.
Every glass of water you leave out a few days "degasses" even at rest and will form microbubbles within it, shaking the glass or stirring the liquid breaks these up
I work regularly with hydraulic fluid and line length + proper bleeding + no air in the system is ESSENTIAL for properly aligning two huge pistons that lift the top of my several ton particle accelerator "lid". Any air bubbles will cause the pistons to move out of relation to each other causing a jam because the piston on each side won't be in sync. Our brake systems are much simpler
My 3 cents
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
59, how did I not realize you were and LRRS guy? You going up for the first event?
Anyway, just agree with everything you said but realized I am having trouble finding the double banjo bleeder. Where are you finding them?
Anyway, just agree with everything you said but realized I am having trouble finding the double banjo bleeder. Where are you finding them?
Senior Member
Superstock
Joined: Nov 2014
Posts: 416
From: Middletown, CT
Smokin Joe try these guys... Bleeding brakes - The stahlbus bleeder valve integrated in a double banjo bolt
Senior Member
Superstock
Joined: Nov 2014
Posts: 416
From: Middletown, CT
Ren,
Thinking a braking system is sealed from the atmosphere is at best wishful thinking especially on an older system. Brakes heat up, fluid expands creates positive pressure, pushes out on the flexible bellows/master cylinder cap gasket, it cools pressure goes negative, the bellows collapses inward, above it is the outside world of moisture laden air.... It gets in, just the way it is, I try not to worry about imperfect seals unless the leak compression gases, or fluids. I just do what I need to do to insure for myself or anyone I crew for never has to say "I couldn't get it stopped the lever came back to the bar",...
Thinking a braking system is sealed from the atmosphere is at best wishful thinking especially on an older system. Brakes heat up, fluid expands creates positive pressure, pushes out on the flexible bellows/master cylinder cap gasket, it cools pressure goes negative, the bellows collapses inward, above it is the outside world of moisture laden air.... It gets in, just the way it is, I try not to worry about imperfect seals unless the leak compression gases, or fluids. I just do what I need to do to insure for myself or anyone I crew for never has to say "I couldn't get it stopped the lever came back to the bar",...
Senior Member
Superstock
Joined: Nov 2014
Posts: 416
From: Middletown, CT
Smokin' Joe probably not going for the opener. I was rained on, snowed on, frozen half to death for 15 years, because I had to be there, now if it isn't sunny and temperate I'd rather stay home... Where are you located? I'm in Middletown, CT
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
Yeah 59 last years opener I had 2 crashes in those frigid temps on the front tire. No way to keep them heated up. Pretty frustrating.
I am going if weather is nice but like to open the campers up and get bikes prepped. Plus a nice break from work so will see.
I am in Queens, NY. Got my license in Bridgehampton in 96. In N garage 12 across from Dunlop with BJ Worsham.
I am going if weather is nice but like to open the campers up and get bikes prepped. Plus a nice break from work so will see.
I am in Queens, NY. Got my license in Bridgehampton in 96. In N garage 12 across from Dunlop with BJ Worsham.
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
Oh, no not 59 degrees, 59 the user name. The temps were 20s F at night and barely breaking out of the 30s daytime so maybe 40ish. High winds and no sun meant tucking the front a lot.
2 crashes in one weekend was more than my usual amount for a whole season.
Plus on the street you are just going straight where I was sliding my knee in 40*, at least until the front went away. (twice)
2 crashes in one weekend was more than my usual amount for a whole season.
Plus on the street you are just going straight where I was sliding my knee in 40*, at least until the front went away. (twice)
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
Also, racing rubber really hates cold, plus my leathers are perf'd so it was mad cold. Usually I am very geared up.
(Brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr)
(Brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr)
Moderator
MotoGP
Joined: Jul 2007
Posts: 5,219
From: Gettysburg, Pa
Senior Member
SuperBike
Joined: Sep 2010
Posts: 1,994
From: Bisbee, AZ
954 Caliper
Finally got around to installing 954 calipers that have been waiting for a long time. Still have the stock master on, but have a 954 master on the bench along with a rebuild kit. The current combo is a bit hard to modulate. Though the biggest issue seems to be the wimpy forks bottoming out under hard braking.
The two black marks define the area that needed to be ground off the allow the caliper to mount up. I thought it was going to be a lot more.
The two black marks define the area that needed to be ground off the allow the caliper to mount up. I thought it was going to be a lot more.
Senior Member
Superstock
Joined: Nov 2014
Posts: 416
From: Middletown, CT
I never have encountered a racer that allowed air into their rear brake system. I think someone is blowing smoked at you. The key is a perfectly maintained easy to modulate at the limit system front and rear plus the skills to use it... Spongy brakes cannot be modulated...
Senior Member
SuperBike
Joined: Sep 2010
Posts: 1,994
From: Bisbee, AZ
There was some discussion in another thread about Zcoo brake pads. Thought it would be good to have some info on them here in the brake mod thread.
Brake Pads ZCOO N004 EX Compound (1 couple for 1 disk) - Specific for Honda VTR SP2/RC51 02-03
Good news for people with stock calipers.
CarpiMoto - Brake Pads - Honda VTR 1000 F
Brake Pads ZCOO N004 EX Compound (1 couple for 1 disk) - Specific for Honda VTR SP2/RC51 02-03
Good news for people with stock calipers.
CarpiMoto - Brake Pads - Honda VTR 1000 F
Thread
Thread Starter
Forum
Replies
Last Post
pbfiredawg22
Technical Discussion
14
Sep 8, 2010 05:48 PM
