www.zxrworld.co.uk

Dunno whether you've managed to sort out a master cylinder, but after looking round on the 'net, it seems that '04 onwards R1's run a 16mm radial Brembo master cylinder, might be worth a punt if you can find 1??

I bought this recently, i've got the gixxer calipers and some HEL braided lines. I'm building up a bit of a trick race/track bike.



Its adjustable reach, ratio and is i bit posh being billet and only 300 grams. I think i'll be doing unintentional stoppies this year

nice!! let us know how you get on with it.

hi i'm looking to upgrade the brake lines but will need a different master cylinder that will take 2 brake lines
and not the single into a splitter that i've got now

any ideas on which route to take ?????

Your current master cylinder will be fine...............if you want to connect two lines then just use a double length banjo bolt with the correct seals

cheers for that cargo i didnt think of that

will give it a go

cheers again

The Brembo MC fits alright and works a treat dont think I could use the original MC as it was too spongy and the lever came all the way back to the bar. Brembo, HEL line and a good bleeding and now its a sharp as anything!

As far as I can make out, most of the time, "upgrading" to a new master cylinder is just that - a new one. in theory, a 14mm (or 5/8", or whatever size) of any vintage is going to give the same pressure from a given effort. The likely improvement comes from the fact that the new M/C will have less wear and tear. My (standard) brakes on the race bike were getting strangely wooden a few years ago, and a very meticulously fitted rebuild kit absolutely transformed them. I had a similar experience a few years ago where braided lines and new seals failed to inspire life into an old NC24s brakes. Same size but newer master cylinder and voila! brakes agian. I run a radial ZX6 now (got it cheap) with the same fitting issues as cargo and was well happy until I snapped a lever (mid race - whole other brown trousers story) and had to refit the original ZXR unit - same bike, same day and absolutely no discernable difference in feel or performance. IT is possible though - that new models have better detail design or manufacturing tolerances?

So you could say I'm a bit of a sceptic - well maintained ZXR brakes are well up to race use, but they are a PITA to keep right. A mechanic relation of mine, sick of failing to get 6 pots bled and performing properly came to the conclusion that the seal grooves had to be cleaned with a dremel and thing wire brush as the tinyest bit of white fur and thus extra radial pressure on the seals and pistons caused them to retract a tiny bit too much and cause the spongy / excessive lever issues that people complain about, although I think the bleeding issue is one of bleed nipple not always at the top of the fluid cavity when fitted to the bike. Bleeding off the bike might help?

Bit long winded but what the hell..........

And - speaking of brown trousers - enjoy - I nearly pooped myself reading it....

http://www.x-h2o.com/showthread.php?884 ... py-Journal


Noel B.

noelb wrote:As far as I can make out, most of the time, "upgrading" to a new master cylinder is just that - a new one. in theory, a 14mm (or 5/8", or whatever size) of any vintage is going to give the same pressure from a given effort. The likely improvement comes from the fact that the new M/C will have less wear and tear. My (standard) brakes on the race bike were getting strangely wooden a few years ago, and a very meticulously fitted rebuild kit absolutely transformed them. I had a similar experience a few years ago where braided lines and new seals failed to inspire life into an old NC24s brakes. Same size but newer master cylinder and voila! brakes agian. I run a radial ZX6 now (got it cheap) with the same fitting issues as cargo and was well happy until I snapped a lever (mid race - whole other brown trousers story) and had to refit the original ZXR unit - same bike, same day and absolutely no discernable difference in feel or performance. IT is possible though - that new models have better detail design or manufacturing tolerances?

So you could say I'm a bit of a sceptic - well maintained ZXR brakes are well up to race use, but they are a PITA to keep right. A mechanic relation of mine, sick of failing to get 6 pots bled and performing properly came to the conclusion that the seal grooves had to be cleaned with a dremel and thing wire brush as the tinyest bit of white fur and thus extra radial pressure on the seals and pistons caused them to retract a tiny bit too much and cause the spongy / excessive lever issues that people complain about, although I think the bleeding issue is one of bleed nipple not always at the top of the fluid cavity when fitted to the bike. Bleeding off the bike might help?

Bit long winded but what the hell..........

And - speaking of brown trousers - enjoy - I nearly pooped myself reading it....

http://www.x-h2o.com/showthread.php?884 ... py-Journal


Noel B.

I'd agree with that................

I've got a radial master cylinder off a ZRX10 or wahteber 1000 superbike it is that the big K makes on my 400 and jolly good it is too but is it better than a new 400 one maybe but not hugely so...................is it better than a old well worn 400 one.....very much so

Funny you mention the ZX6 lever snapping.................mine broke after it just touched the side of the van while reversing it out. There is a weak spot in the middle of the lever that I can only assume is there to allow the lever to break without doing damage to the master cylinder itself ? ? ?

i only want to upgrade the master cylinder due to the age of the machine its on a E plate and was thinking maybe its time to upgrade !!!!

what does anyone think ?

Any master cylinder that physically fits and is intended for use with four piston calipers will work just fine and be better than an old worn one.

However you can buy a seal kit to bring an old one back to life


pay your money and take your choice


A new Brembo seems to be the master cylinder of choice for many...................but it aint cheap

As a matter of interest I'll be putting a new seal kit into the master cylinder on my ZRX 11 shortly cos the brake is truely awful

hey cargo
changing all the oil seals on the master cylinder is it a hard or fiddley job ?

its not a job i have done before

The seals aren't too bad - its the little internal circlip that holds the piston in that can be awkward. Can be a two man job as the piston sometimes needs to be held in against the spring pressure to remove.

its do-able though - just take yer time and leave everthing surgically clean when you're re-assembling.

Noel B.

cheers for that noelb

think i give it a try
what harm can it do eh ??? just end up with no brakes lol

is there anything on the market to help with the spring ?

My ZRX4 came with 6pot Tokicos as standard running a 5/8" master , brakes were good but not stunning. I then changed to a 19mm Radial Nissin master and thats when it got interesting - the effort needed by me was reduced to one finger pressure. Giving a "mitt full" would either put me over the bars or make the front end slide out ! Actual braking performance marginally better but that could be persception of " ease of use " rather than actually being better - what made a difference was pads, changing from OEM to Daytona Red turned them into eyeball out the socket stopping ! Which makes for later braking if your needing to shave some time of laps, the Dyno tuners remark was " massive brakes for a 400! "

The ZRX when I got it , the front brakes worked and calipers were covered in dust & fork oil , I washed them down and fitted OEM pads (had a new set sitting). I would assume the master has never been overhauled and I haven't even changed the fluid, why? Cause these brakes are also one finger operation, braking is poor (lack of feel) down to the pads so this year they will get swapped out for the Daytonas. Before the rebuild I picked up a Brembo 16x18 master to fit but because the OEM (apart from braided lines) is working so good I don't see the point in changing just now.

Advantage over cast & billet:
Cast calipers and masters are porous and under extreme braking & race conditions as the fluid heats up it can/does migrate into the casting giving poor feedback , sponginess and fade. Once cooled down it in turn can/does draw in moisture so again compromising performance.

Billet does not have these problems and they also transmit heat more effectively than cast so braking becomes more stable with out fade.

Manufacturing techniques improve all the time so modern cast will give as good as billet on the road under standard conditions , modern sport bikes are tested on track (as are all bikes) and the test riders do push them but they are not doing 25 laps at MotoGP speeds and the brakes aren't specified for that challenge. So fitting a modern master you are getting a better product than your 15yrs old one - the fact the seals are newer etc does bare something towards the aparent gains but it is also the casting process, machining and modern material technologies too.

Fit what you can afford, if you can't stretch to exotica then try a modern radial or even a standard 5/8th. As for me I am still using my 21yr old set-up and will do until such times I do a complete change but I don't do track and the most I ever push my bike is up on the mountain roads over a 5 mile course and they are more than ample for that just my nerve needs some tweaking

MM!