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Discussion Starter #1
Hey peeps, I've got some some more parts coming to do another bit of an upgrade... lol, always modding this thing!
So recently I've done some changes to give it another bit of a bump up in performance, now over 60hp at the wheels, but that post will come later as still sorting some things out with the tune for it.
But with more horse power comes the need to have better stopping power too. I've got a front caliper bracket coming from rsvracing (thanks @Oyabun for the recommendation) and have a larger, full-floating caliper from a Triumph Street Triple to bolt up to it once the bracket arrives. (Still single rotor braking)
I expect that with the different caliper design, more fluid/force will need to go through it than what the oem master cylinder does. That, and with the clip-ons I have, I hate the look of the reservoir sitting on such a steep angle and seek to remedy that with a setup that has a remote reservoir.

Looking for recommendations and what to look out for (i.e. piston size) with upgrading the front master cylinder.

I was considered the Brembo rcs19 albeit a bit exy, but even more so with the exchange rate currently, that's well and truly out of the ball park for budget allowance.
Bonus points if can get something that has a matching (cable) clutch lever as well.

I see a few on eBay at varying degrees of 'trustworthness', I like the look of these Adelin ones and comes with matching clutch lever. Although not the cheapest Chinese offering, still a little dubious putting my faith in them. Anyone else had experience with these?

Or maybe something that can be retrofitted from another bike that already has similar config (large full-floating caliper on single rotor)
 

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Don't forget that the rotor dissipates most of the heat from braking. Dual rotors help but for single rotor how about one with larger surface area to match your bigger caliper?
 

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Discussion Starter #3
The factory
Don't forget that the rotor dissipates most of the heat from braking. Dual rotors help but for single rotor how about one with larger surface area to match your bigger caliper?
The standard rotor is already fairly large by comparison. At 320mm it's slightly larger than the STriple's at 310mm. The STriple's caliper has larger pistons pressing against longer pads. But yes, I anticipate some swift riding will bring on brake fade sooner.

The next step up would be a full front end swap to get dualies, but that's a lot more than in willing to go at this time; this is the middle ground
 

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Looking forward to your post on engine mods.
 

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Discussion Starter #6 (Edited)
A bit more research and found a site that gives the maths to equate it.
Force ratio from the formula, in plain english:
(total surface area of pistons on one side of each caliper [so you will get the same result on a 2-piston sliding caliper as on a 4-piston fixed caliper]) x (number of calipers) / (surface area of master clinder piston)
In maths terminology that's:
(((Pi x R^2) + (Pi x R^2))x n) / (Pi x R^2)

Stock MC bore is 1/2" (12.7mm) and caliper pistons are both 27mm [edited]. The Triumph STriple R caliper pistons are 25mm and 32mm.
So using that formula and plugging different sizes either side to see the difference, shows that 15mm MC bore would be the closest albeit a less ratio, and 14mm 2nd place with higher ratio.
If I read the explanations right, moving to a lower ratio means more hydraulic force but longer lever travel... bad if your lever bottoms out on the grips before full force applied. And moving to a higher ratio is opposite, less force but also less lever travel.
72189


I decided to go with 14mm bore as it's quite a common size, and I found a company that sells genuine Nissin ones at a reasonable price. So win, win :)
 

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Hey peeps, I've got some some more parts coming to do another bit of an upgrade... lol, always modding this thing!
So recently I've done some changes to give it another bit of a bump up in performance, now over 60hp at the wheels, but that post will come later as still sorting some things out with the tune for it.
But with more horse power comes the need to have better stopping power too. I've got a front caliper bracket coming from rsvracing (thanks @Oyabun for the recommendation) and have a larger, full-floating caliper from a Triumph Street Triple to bolt up to it once the bracket arrives. (Still single rotor braking)
I expect that with the different caliper design, more fluid/force will need to go through it than what the oem master cylinder does. That, and with the clip-ons I have, I hate the look of the reservoir sitting on such a steep angle and seek to remedy that with a setup that has a remote reservoir.

Looking for recommendations and what to look out for (i.e. piston size) with upgrading the front master cylinder.

I was considered the Brembo rcs19 albeit a bit exy, but even more so with the exchange rate currently, that's well and truly out of the ball park for budget allowance.
Bonus points if can get something that has a matching (cable) clutch lever as well.

I see a few on eBay at varying degrees of 'trustworthness', I like the look of these Adelin ones and comes with matching clutch lever. Although not the cheapest Chinese offering, still a little dubious putting my faith in them. Anyone else had experience with these?

Or maybe something that can be retrofitted from another bike that already has similar config (large full-floating caliper on single rotor)
How the heck do you get that sort of horsepower 🤔👍
 

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Discussion Starter #10
@ADIOS600 I'll keep this thread relevant to the topic of the master cylinder mod.
Can continue discussion of the bike in new thread for my bike, once created.
But yes, the limiter does get bashed on occassion and after 90K kms I think the Honda reliability is still there ;)
 

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Discussion Starter #12
So a bit more on this progress... The STriple caliper I acquired is NOT actually suitable for fitment. I found calipers come in a couple different flavours, a high-mount like the STriple where the bolt block that mounts to the bike is ~40mm high, and then standard mount which is ~30mm high. I tried shortening the caliper but that was a bit of a fail, without the proper tools or means to hold it precisely. So admitting defeat I did some more hunting and acquired a different caliper with the specifications I need, from a 2008-2016 CBR1000RR. This one comes with even bigger pistons 30/32 versus the STriple's 25/32, so a different Master Cylinder is required. Thankfully my last order for the 14mm had not yet been fulfilled and was able to cancel that order, and now on the hunt for a compatible 5/8" (15.87mm) MC.

Additionally, my previous calculations had an error [was missing () for correct calc] and on top of that I have also learnt of other factors for consideration, the inter-axis ratio and the MC type - axial, radial or semi-radial.
The inter-axis ratio is from two measurements based off of the lever pivot point - pivot-to-hand divided by pivot-to-piston distance.
Pivot-to-piston is fixed by the master cylinder design, the 500 stock is 25mm.
Pivot-to-hand is defined by the user... basically grip the handle normally and mark the mid-point of where you apply force on the lever, measure that distance from the pivot.

I've got my MC-to-caliper ratio acceptable using a 5/8" bore, 15.5:1 stock vs 15.28:1 with the different caliper.
Now to choose a suitable Master Cylinder which from my hunting appears to be in a few different flavors of pivot-to-piston of the very few that actually state it or replied to enquiry; I'm finding 20, 22.5 & 25mm.
To get closer to the stock overall leverage ratio, being the MC-to-caliper * inter-axis ratio I can adjust the position of where the lever mounts on the handle bar in respect to my hand position.
You can see from the below, using the same MC ratio but a different pivot-to-piston that adjusting piston-to-hand position can net a very close overall ratio. I'm limited by moving it outboard by 10mm to 80, hence the 20mm being a bit more than the others.

72201


From what I'm gathering the MC-to-caliper ratio affects how effective the brake set is; whereby a lower ratio equates to less lever pull distance but less pressure at the same comparative distance. Too low of a ratio and it can become what some describe as wooden or like an on-off switch. A higher ratio will give more pressure at the expense of lever travel, where some describe as being spongy or where the lever hits the throttle before full brake application is achieved.
The inter-axis ratio has somewhat of a similar affect but more for lever "feel" for the user, in that a higher ratio (e.g. a shorter pivot-to-piston) will equate to a shorter lever pull applying on the force for the MC-to-caliper ratio.

Going from standard axial MC to radial MC is another kettle of fish that I'm not at all qualified to comment on, though apparently a larger bore radial like a 19mm is equivalent to 5/8" axial bore. Radial MCs are out of my budget range though, so I'm not delving into the maths with those ones much at all.
There's also a bunch of other factors for brake effectiveness like rotor size, number of calipers, hose line and pad types... again though not the purpose of this thread for solely finding a compatible master cylinder to suit a given application.
 
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