[Ebster1085]

So we have all been over the inherent issue with the MC on the 05/06 model. Kawi addressed this with a redeisgned piston that you can get with a cheap rebuild kit. Myself among many others did this with great results. Since doing the rebuild and installing Galfer lines, I no longer get a mushy lever, no longer lose pressure in the system, and have had consistent powerful brakes ever since.

My question is this. Why is the lever pull for the 05/06 MC longer than other models? I still have a firm lever that ends with a hard stop, so I know there are no bleeding or pressure issues. But, I do notice that the lever pull is just longer than most other sport bike MC's I have experience with. This is extra confusing to me because the 05/06 piston is actually the biggest of all teh ZX6R pistons which would lead me to believe it would move more fluid with less pull.

I am in no way complaining because I actually love my current brake setup and it has worked wonderfully for me at the track, I am just curious why this is the case. Can anyone chime in?

 

[Manolo]

what about diameter bore of the M/C? maybe its smaller? :dunno:

 

[Ebster1085]

what about diameter bore of the M/C? maybe its smaller? :dunno:

This is extra confusing to me because the 05/06 piston is actually the biggest of all teh ZX6R pistons which would lead me to believe it would move more fluid with less pull.

The 05/06 MC actually has the biggest bore of the ZX6 models. I believe its 21mm whereas later models were 19mm.

 

[Ebster1085]

Anyone got a real mechanical explanation??

 

[Scorpi0]

Maybe the piston on the caliper has a bigger bore??

 

[Ebster1085]

Maybe the piston on the caliper has a bigger bore??

The 05/06 MC actually has the biggest bore of the ZX6 models. I believe its 21mm whereas later models were 19mm.

Haha...seriously?

I would think that a bigger bore would make for a shorter lever pull, but maybe I am not looking at the dynamics correctly.

Wouldn't a larger bore, and subsequently a larger piston, would push more fluid through the lines per the amount of pressure applied to the lever?

 

[Scorpi0]

Yes, but I was talking about the pistons that actually push your brake pads out. If that bore is bigger youre gonna have to move more fluid to push it out.

 

[skidooboy]

14mm radial master in the 05-06, 16mm radial master in the 07+, this gives you different pull and stop features in each master. that is the difference.

like buying a 18,19, or 20mm brembo master. pushes more fluid, with less lever travel and finger pressure. Ski

 

[Ebster1085]

Yes, but I was talking about the pistons that actually push your brake pads out. If that bore is bigger youre gonna have to move more fluid to push it out.

Hmmm..not sure about the caliper design, but I guess that 100% could be the cause of the longer pull.

Either way, I really like the way the brakes perform now, was just really hoping someone could give me a legit explanation as to why the pull is longer.

 

[Ebster1085]

14mm radial master in the 05-06, 16mm radial master in the 07+, this gives you different pull and stop features in each master. that is the difference.

like buying a 18,19, or 20mm brembo master. pushes more fluid, with less lever travel and finger pressure. Ski

Are you 100% certain the MC piston on the 05/06 is only a 14mm radial and that the later models are larger? I could have sworn I read somewhere that the piston on the 05/06 was larger.

This is from another thread I found while researching:

Tried the '07. It seems a bit better, but the the lever pull still pretty much sucks. It looks like it's going to be the calipers after all. I found a set on eBay and picked them up, so we'll see. Does anyone know the bore of the 2009 master cylinder? The '05 is 3/4", the '07 is 11/16", and I'm wondering about the size of the 2009. If it's 11/16", it would be better to use my factory 2005 master, and sell the '07 I just bought. We'll see.

Edit: Researched this and found the 2009 is 11/16" as well. Basically, with this information, the ultimate braking setup for the front end of the '05/'06 bikes will be the factory master with a rebuild, braided lines, and the front calipers off a '09. I'll update in a few days when I get the stuff in and get a chance to try it. I did get basically race pads though, so I probably will have a good lever, but the brakes won't be outstanding until I hit the track again. I'll keep you all updated. No one else should have to go through this.

 

[skidooboy]

05 -06 has a smaller bore for sure than the 07+, they (mfg) wouldnt go smaller and get less brake feel, they would go bigger. not 100% sure on the sizing. could be 14 and 16 or... could be 16 and 18.

the way to tell them apart is, the 05-06 are brownish in color the 07+ are black.

bigger is better, (to a point) your results may vary. Ski

 

[Ebster1085]

05 -06 has a smaller bore for sure than the 07+, they (mfg) wouldnt go smaller and get less brake feel, they would go bigger. not 100% sure on the sizing. could be 14 and 16 or... could be 16 and 18.

the way to tell them apart is, the 05-06 are brownish in color the 07+ are black.

bigger is better, (to a point) your results may vary. Ski

Thanks dude, pretty sure you are spot on and this is in line with what I have experienced braking on my 06 versus braking on the newer ZX6's.

I wouldnt necessarily say that bigger is better, though. Many would argue that a longer pull provides better feel.