99 zx6r front master cylinder work on a 99 f4?
 

anyone tell me if i can use a front master cylinder from a 99 zx6r on a 99 f4?

Yeah, you can use it. However, I'd recommend just getting one from an F4i to use.

it's a simple hydraulic system. you could use a TON of different master cylinders.... all that has to happen is your lines and bolt have to fit the master so that there are no leaks.


....and the master cyl has to mount to a 7/8 in. bar and you'd probably need the lever

nah conrice lol im waiting for my 11.5 inch bars to come in, they r 2 inches longer then stock

Key to the whole issue is the size of the master cylinder piston size. Smaller will give higher psi at the calipers, but will have more lever travel. Same size will do the same psi. Larger will have less psi at the calipers with less lever travel, so to get equal power you have to squeeze harder.

The lever ratio will play a factor too. The length of the lever from the pivot to the plunger rod as compared to the length of the lever where it is gripped will make a difference too.

If I am permitted, as a new member, this chart is what was posted on the VTR1000 Firestorm site by a member there.

Attachment 42426

If it does not show up and the link I put up doesn't work, go to the VTR1000 Firestorm forum and look up the post on Brake Caliper upgrade in the Workshop section. It's an interesting thread. I was looking at it when planning to do four piston brakes on the Zephyr... which is still in the works, but I got a full CBR900 system including the master cylinder, but I still kept the information in a file.

Hope this helps a bit for you and others.

ok i just wanted to no since i may add a gsxr front brake master for my front brake or my rear brake set up

Reread my post, I added the other information that made it informative - the calipers tested and such.

Go to the forum where that was written. The guy was using a GSXR for it I think. Funny thing I found was that the Kaw six piston set ups used the same size master cylinder piston my two piston Zephyr used. It's all about master cylinder piston area versus caliper piston area.

Well, apparently I can not edit this forum, so here's a rehash:

Intersting article in the Feb PB mag on caliper and MC upgrades on their project GSXR1000K1 which as standard is fitted with 6 piston calipers and 15.6mm MC.

They tried 4 set ups, stopping from 100mph, measured in metres.
a) stock with old stock pads - 104m to stop
b) stock with new EBC HH pads - 93.7m
c) 4 piston Tokico calipers off SV1000 [they say 10% less pad area but 6% more piston area than stock] with EBC HH pads and stock MC - 86.8m
d) as c) but with a big bore [18.75mm] MC of a GSXR 750 K4 - 97.5m

What the data logging shows is that the hydraulic leverage ratio in set up c) was most powerful, and the big bore MC made the leverage ratio worse so had reduced stopping power.

But the test rider feed back was the opposite:
with set up c) tester said "initially these felt like we had gone back to set up a) then I realised I had much better feel; they seemed smoother and more controlled. There was more lever travel but the brakes felt more progressive after the travel was taken up. All in all I didnt think "wow these are great", it felt like I had less brakes"
With set up d) tester said "it feels like there was a lot more braking power with less effort"

Surprise was that the performace was the opposite!!! the big bore MC gave a much firmer lever, so it felt good, but stopped worse as it generated less pressure in the calipers .... 12% worse stopping distance. the set up d) bike was still doing 30mph when the set up c) bike was stopped.....

Shows that the laws of hydraulic ratios is correct, but what the hand feels can be misleading to the brain.

So I have updated the XL sheet to show the GSXR ratios as well so you can compare the relative ratios in the data above to the various firestorm options.


I used the F4i calipers on the GSXR example as they gave 7% more piston are than the data I had for the GSXR 6 pots, and you can see that set up c) improved hydraulic ratio by about 7% over stock, and then adding big bore MC reduced it by close to 30%.

Below the GSXR stuff are just a look see at what you get with various options including the stock VTR parts.

Attachment 42378

first option looks to have great leverage, but I think the lever would come back to the bar before the biting point!
2nd option would be like the GSXR example set up d) very solid lever feel, but crap braking performance!
3rd option would be similar to 2nd option, but not as crap.


Now it probably makes more sense and is of more use to anyone here.

The gist of the whole thing is to know your leverage factors on the caliper to master cylinder. Lower is harder braking, but more lever travel, as evidenced by the testing. A hard short travel lever may be deceiving in performance.