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Discussion Starter #1
I have a 2013 F4. I've installed a STM clutch and 30mm clutch slave. These additions have greatly improved the ability to modulate the clutch during launch. I would still like the clutch lever to have more throw so that it is easier to modulate.
If I replace the stock Nissin clutch master cylinder with a Brembo Radial 16x16 RCS, will the lever have more travel than with the stock Nissin master cylinder? The 16x16 Brembo RCS has a 16 mm bore and lever ratio of 16 which would result in the largest lever movement for a Brembo master cylinder.
 

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IF it has a larger bore and a larger stroke than the NISSAN, then it will move more fluid per distance travelled than the Nissan will.

Seems to me that would shorten the actuation distance for the slave cylinder.

As for "modulation", it will certainly change the feel.
 

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I assume you want a smaller diameter and a smaller ratio.

The 16 is not the ratio, but the distance from the lever pivot to the centre line of the piston, the actual ratio is dependant on where you grip, but for a 16 mm pivot its ~8.7 and ~7 for a 20mm pivot. However assuming you grip in the same place then the 16 will give you the greatest mechanical advantage when compared to an 18 or 20.

For some reason I think the Nissin is 17mm but not sure on the pivot, I could take a look tonight and let you know. I use a Galespeed VRE 16mm dia x 18-16mm lever pivot, pivot is about 17mm I think. I still use the stock slave, once the clutch mod was done to the anti-judder, she launches very well.

If you assume a clutch stack movement of say 0.75mm then a 16mm piston will need to move 2.6mm to achieve the volumetric displacement you want, vs 2.3mm and 1.9mm for a 17mm and 19mm bore respectively. I'd advise buying an adjustable pivot in a 16mm bore, that way you can effectively tune the feel and the lever throw based on your feel.
 

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Discussion Starter #4
Thanks Danssoar. It think you are right. I'll get the 16 RCS LL. It has the adjustable pivot distance for 16 and 18 mm.
It is extremely difficult to find information on the Nissin master cylinder dimensions. Thanks for your response.
 

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Discussion Starter #5
I installed the Brembo 16 RCS clutch, set the pivot point to 16 mm, and it is much smoother. It now takes a longer pull to fully disengage or engage the clutch, but, of course, that means it's easier to modulate.

Now the quick shifter doesn't work. The problem is that the Brembo has no place to attach the stock clutch position sensor. So, I have ordered a pressure sensor attachment (see picture). It was $18 including shipping from Carpimoto. It replaces the stock banjo bolt. It has 10 x 1.0 threads. The pressure sensor on the end of the banjo bolt makes it longer. I can see that it will interfere with some black fairing parts. I purchased a heat gun and intend to soften the black plastic and mold it so that it gives clearance to the pressure sensor.

I don't know why it's not more widely known that you have to have a clutch position sensor for the quick shifter to work. I did a lot of study before choosing the 16 RCS, but it was never mentioned.
 

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I use galespeed and you can have a switch option. Its a common issue that people fit aftermarket levers that don't activate the switch properly. Also there are switches for the brembo if i recall


From my part I forget that people may not know as it's obvious to me, as done this on many bikes and the clutch switch is an integral part.

I'd put the hydraulic sensor on the other end i.e. the slave cylinder, the switch does not have to go on the master cylinder, I've also fitted them into a t piece in the line to keep them protected.
 

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E.g
 

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Discussion Starter #8
I attached the Brembo pressure switch to the Brembo RCS 16 clutch master cylinder. Now there is no warning light and the quickshifter should work (haven't ridden it yet).
One thing I anticipated is that the banjo bolt with the pressure switch is longer than a normal banjo bolt (see red pressure sensor in photo below). It is long enough to hit the black plastic fairing, preventing steering to full lock. So I used a heat gun to soften the plastic and simultaneously pressed on the plastic with the metal capped handle of a large screwdriver. There is now clearance for the steering head to turn to full lock (see dimpled plastic below). The dimpled plastic is really not an aesthetic problem. It's black and generally shaded.

The new Brembo RCS 16 clutch mastercylinder, set on 16, is very light to pull, and will be easier to modulate. There's nothing else I can do. I have the STM clutch, 31 mm clutch slave, and now the RCS 16 set on 16.The clutch pull is now light enough to allow sensitive modulation for good launches.
 

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Discussion Starter #9
I rode the F4 today after installing the brembo pressure connector, and everything performed as usual. The quick shifter is operational again and there are no "STOP" messages on the display :) .

One more thing to add about the Brembo pressure switch installation. The Brembo electrical connector looks like it might fit your stock MV connector, but it doesn't. My solution was to cut off the connectors and replace them with bullet connectors.
 
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