Brakes!

Hi guys,

The brakes on my 1999 ZX7R have never been exactly startling - I can't use 2 fingers to brake as I trap the other 2 between the lever and the bar! On trackdays, they work but I want better...

God - the brakes on my old pointy SV were better and that's known as one of the SV's weak points! The ZX7R has 6 pot calipers whereas the SV has 2 pots!!!

Well, needless to say, this is now bothering me and I've found myself riding it less! (once since my last trackday, MONTHS ago! Those of you who know me will know that this is far from normal!)

I've been looking for advice and I know I need to strip, clean & rebuild the calipers, bleed the (braided, twin) lines - which I plan to do as a bit of a winter project (along with everything else that needs doing round the house!!)

I'm considering replacing the master cylinder, as I've read that a 19mm bore (radial) master cylinder will drastically improve things but what do the 2 sets of numbers mean on master cylinder specs????

I'm also going to replace the pads, which as far as I am aware are the OEM jobbies... Any suggestions - I have no real idea what to go for!?

As a last resort, it has been suggested to replace the Tokico 6 pot calipers with Nissin 4 pots - like those fitted to Bandit 1200s, as they bolt straight ion and are supposed to be much better!

Any ideas/suggestions/experience/advice!!??

have you ridden another zx7 the same year? if you have, are they the same.
if not then the rebuid clean etc should work/help.

Originally Posted by jamesrichardson

have you ridden another zx7 the same year? if you have, are they the same.
if not then the rebuid clean etc should work/help.

Unfortunately not but I have pulled the lever back on a few and it doesn't come back nearly as far when at a stand still!
Everyone I speak to says they should be really good - better than the Sv any how... My T595 brakes were better as well!

Are they bled right? Sounds to me like not. Id go and get them serviced propper like. Or do it yourself. They arnt supposed to be amazing brakes compaired to modern 4 pots but they should be a damn sight better than SV brakes.

Might be worth seeing what pads you have in as this can effect the braking a LOT!

Originally Posted by coombest

my old pointy SV were better and that's known as one of the SV's weak points!

No, the suspension is the weak point on the SV. There is nothing wrong with the SV brakes, more than enough for the bike, and when people start moaning about the brakes they tend to need to a service.

Originally Posted by coombest

I'm considering replacing the master cylinder

Have you considered servicing the callipers, the master cylinder on the ZX7R is a good one but the 6 pots need more regular attention to them than 4 pots.

Yeah I would agree. Services them (clean the carp out and stick some red rubber grease on the seals) and think about getting new pads all around if that does not seem to do anything. Remember to bleed from the nipples! as well as the banjo bolts and the banjo on the master cylinder. If you spend a good 15-30 mins finding all the air in the system they should work peachy.

[yorkie_chris]

Are they same tokico as on SRAD?

Basically no point fitting a stupidly powerful m/c, as it sounds like it's flex in old naff lines that's problem. So moving less fluid with a greater leverage isn't going to help matters.

Try things in this order. It's also order of cheapest first

Rebuild OEM stuff clean with fresh fluid.
New pads, maybe HH.
Braided lines.
Fork oil change and look at spring rate. (zx7r I rode was quite harsh, but that was set up for a fat git.)

Then consider master cylinder.

[punyXpress]

Originally Posted by coombest

Unfortunately not but I have pulled the lever back on a few and it doesn't come back nearly as far when at a stand still!
Everyone I speak to says they should be really good - better than the Sv any how... My T595 brakes were better as well!

Can you feel how far the lever moves before making contact with plunger?
Then how far it moves before pads make firm contact with discs?
If the latter seems excessive, the pistons aren't returning properly. Either way, youv'e spent nowt ( so far )

Originally Posted by coombest

Hi guys,

The brakes on my 1999 ZX7R have never been exactly startling - I can't use 2 fingers to brake as I trap the other 2 between the lever and the bar! On trackdays, they work but I want better...

God - the brakes on my old pointy SV were better and that's known as one of the SV's weak points! The ZX7R has 6 pot calipers whereas the SV has 2 pots!!!

Well, needless to say, this is now bothering me and I've found myself riding it less! (once since my last trackday, MONTHS ago! Those of you who know me will know that this is far from normal!)

I've been looking for advice and I know I need to strip, clean & rebuild the calipers, bleed the (braided, twin) lines - which I plan to do as a bit of a winter project (along with everything else that needs doing round the house!!)

I'm considering replacing the master cylinder, as I've read that a 19mm bore (radial) master cylinder will drastically improve things but what do the 2 sets of numbers mean on master cylinder specs????

I'm also going to replace the pads, which as far as I am aware are the OEM jobbies... Any suggestions - I have no real idea what to go for!?

As a last resort, it has been suggested to replace the Tokico 6 pot calipers with Nissin 4 pots - like those fitted to Bandit 1200s, as they bolt straight ion and are supposed to be much better!

Any ideas/suggestions/experience/advice!!??

Sounds like a bleeding problem to me, I had to do a similar thing to you to my CBR to improve the braking. Although with mine, it was mostly in my mind, because I would ride the 750, and then get on the CBR which had inferior (but 'correct') brakes...

If you want to bleed the brakes I recommend this kit http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=360075265985 - that is the exact one I bought actually

The trick I found is to fill the system from the nipples (slowly - apparently you can pop seals if not careful). Then, making sure there's enough fluid in both the syringe & the master cylinder reservoir, push the fluid through, then suck it back, keep doing this until you no longer see bubbles coming back out into the syringe. You probably won't see anything on the master cylinder side as it just opens into the air.

Two tips though:
- When you get air bubbles coming out on the syringe side, put the syringe higher than the nipple so the bubbles go to the top of the syringe and don't feed back in if you squeeze the syringe again.
- Keep an eye on the master cylinder & syringe levels as the last thing you want to do is reintroduce air through either.

RE: master cylinders...to be honest I don't know what the numbers refer to, I did try to find out (I upgraded my CBR's master cylinder, see sig!). I think 18/19mm is around the norm for a master cylinder though.

In terms of changing it, if you go for a bigger bore you will get a firmer lever feel, BUT technically it will actually need more effort on the lever to get the same brake power. A smaller bore has the opposite effect - more travel but less actual effort required.

The reason is (may get corrected here by an expert but this is roughly it!) that because this is a hydraulic system pressure on one end is reflected pretty much directly at the other end - i.e. psi at one end = psi at the other end. So if you have a master cylinder and you apply 1psi to it, you get a certain amount of braking power. If you go for a larger bore, you have to apply more force to get 1psi all over the area of that bore (remember it's per square inch, so more inches = more effort required for the same psi). But the upside is that you move more fluid for a given movement of the cylinder - because the area is larger. So it doesn't need to move as much to effect braking - hence, a firmer lever.

Originally Posted by Dangerous Dave

No, the suspension is the weak point on the SV. There is nothing wrong with the SV brakes, more than enough for the bike, and when people start moaning about the brakes they tend to need to a service.

I konw the suspension was the weak point but the bbrakes were generally mentioned in a second breath when I had mine... I was also very light at the time I had mine (9 stone), so neither really bothered me at all!

Originally Posted by Dangerous Dave

Have you considered servicing the callipers, the master cylinder on the ZX7R is a good one but the 6 pots need more regular attention to them than 4 pots.

As mentioned in my original post, this is planned as a winter job... I also did it just after I bougt the bike (Feb '06), as I thought they could/should be better than the were. There was a marginal improvement!

Originally Posted by yorkie_chris

Are they same tokico as on SRAD?

Yes, I believe they are.

Originally Posted by yorkie_chris

Basically no point fitting a stupidly powerful m/c, as it sounds like it's flex in old naff lines that's problem. So moving less fluid with a greater leverage isn't going to help matters.

Try things in this order. It's also order of cheapest first

Rebuild OEM stuff clean with fresh fluid.
New pads, maybe HH.
Braided lines.
Fork oil change and look at spring rate. (zx7r I rode was quite harsh, but that was set up for a fat git.)

Then consider master cylinder.

As mentioned above - cleaned/rebuilt the calipers before to little effect, was planning in doing so again this winter...

Fitted new Goodridge braided (twin) lines at the same time and filled with new brake fluid (what turned out to be the best stuff you can get, according to the guy at the garage where I bought the bike!) I took it to him for his opinion and he bled the lines some more but to little effect!

I'm very happy with the suspension now - I took the bike to All Bike Engineering in London and had it re-worked. They re-oiled and re-gassed everything and the rear shock needed a new rod. I then had it fully set up for me at a Focussed Events Trackday at Brands Hatch by their suspension 'guru' bloke... All in about £450 spent on that and it was well worth it - it does exactly what I want it to do, when I want it to do it now....... Except stop well enough!!!!

Originally Posted by punyXpress

Can you feel how far the lever moves before making contact with plunger?
Then how far it moves before pads make firm contact with discs?
If the latter seems excessive, the pistons aren't returning properly. Either way, youv'e spent nowt ( so far )

Not sure - I will have a look when I'm next out in the garage... Either way I'm gonna service those calipers!!

Cheers muffles, I like the look of that kit - and it's a rather appealing price! Think I'll find me one of them and give it a bash!!