Another year, another round o' mods...
01-15-2011 | 08:00 AM
#1
Thread Starter
Senior Member
MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
Another year, another round o' mods...
The big piece (engine rebuild) mostly out of the way, I am now turning my attention to a few other items as the bike lies dormant for the winter:
- instrument cluster: changed over the stock analog dials to a digital unit from RC51 (done!)
- gas cap: replaced the screw-type racing gas cap with a RCM billet piece (see pic)
- hugger: bought a hugger from Airtech (see pic; wanted one with no chain guard, only one I found was this one), will need paint (black)
- MCs: replacing the OEM clutch and NIssin 19x18 brake radial with a set of OEM Ducati Monster 1100 Brembos. The main reason for the change is that the Brembo is a 19x16, which should give me added leverage and feel at the lever. I picked up a set of dark blue Pazzo levers to go along with the new master (will be parting with the existing bits shortly). I alsogot a good deal on a Discacciati billet 16x19 brake radial which I may try (matched to SP-2 calipers) if this is set-up does not give me the results I want. Otherwise, the Disca and SP-2 will be on the market (watch for them!)
- calipers: replacing my existing (98-99) 900RR front and OEM rear with a set from an F4i (same units, just all black, it's an aesthetic thing; existing units to be sold shortly)
- rearsets: will be installing the K&T rearsets I bought from Beau (captainchaos)
- windscreen: installing a "cool blue" iridium double-bubble Powerbronze unit
- exhaust: repacking Akra cans (bought a set of dB killers too, which I will surely try at some point; cops around here are starting to monitor non-OEM exhausts....)
- airbox: sent my recent (post-rebuild) dyno charts to Roger Ditchfield who stated that my results are not as good as they could be, feels the stock airbox is choking the engine, so I will trying to run a lid-less set-up (have a spare box I can cut up). He recommended I run a K&N filter and gave me the proper jetting specs to run (all jets in hand and ready to install). The improved breathing should land me a few extra lb-ft and hp...
Will likely be parting with my almost-new BMC street filter shortly too.
- tires: just had the rear tire replaced with a Power Pure 190/55 (my PVM rim is a 6-incher), will also be getting the front replaced with a matching Pure. Front tire valves will be replaced with an aluminum 83-degree red anodized unit (as on rear)
- miscellaneous: blue titanium swingarm pivot bolt, various other Ti bolts and nuts (found a good supplier of relatively inexpensive Ti)
and that's it for now. As you can see, I will parting with a few nice bits in teh coming weeks if anyone is interested. Looking forward to getting it all done and out on the road
- instrument cluster: changed over the stock analog dials to a digital unit from RC51 (done!)
- gas cap: replaced the screw-type racing gas cap with a RCM billet piece (see pic)
- hugger: bought a hugger from Airtech (see pic; wanted one with no chain guard, only one I found was this one), will need paint (black)
- MCs: replacing the OEM clutch and NIssin 19x18 brake radial with a set of OEM Ducati Monster 1100 Brembos. The main reason for the change is that the Brembo is a 19x16, which should give me added leverage and feel at the lever. I picked up a set of dark blue Pazzo levers to go along with the new master (will be parting with the existing bits shortly). I alsogot a good deal on a Discacciati billet 16x19 brake radial which I may try (matched to SP-2 calipers) if this is set-up does not give me the results I want. Otherwise, the Disca and SP-2 will be on the market (watch for them!)
- calipers: replacing my existing (98-99) 900RR front and OEM rear with a set from an F4i (same units, just all black, it's an aesthetic thing; existing units to be sold shortly)
- rearsets: will be installing the K&T rearsets I bought from Beau (captainchaos)
- windscreen: installing a "cool blue" iridium double-bubble Powerbronze unit
- exhaust: repacking Akra cans (bought a set of dB killers too, which I will surely try at some point; cops around here are starting to monitor non-OEM exhausts....)
- airbox: sent my recent (post-rebuild) dyno charts to Roger Ditchfield who stated that my results are not as good as they could be, feels the stock airbox is choking the engine, so I will trying to run a lid-less set-up (have a spare box I can cut up). He recommended I run a K&N filter and gave me the proper jetting specs to run (all jets in hand and ready to install). The improved breathing should land me a few extra lb-ft and hp...
Will likely be parting with my almost-new BMC street filter shortly too. - tires: just had the rear tire replaced with a Power Pure 190/55 (my PVM rim is a 6-incher), will also be getting the front replaced with a matching Pure. Front tire valves will be replaced with an aluminum 83-degree red anodized unit (as on rear)
- miscellaneous: blue titanium swingarm pivot bolt, various other Ti bolts and nuts (found a good supplier of relatively inexpensive Ti)
and that's it for now. As you can see, I will parting with a few nice bits in teh coming weeks if anyone is interested. Looking forward to getting it all done and out on the road
01-15-2011 | 08:23 AM
#3
Thread Starter
Senior Member
MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
Well, I looked at replacing the fairing stay and sub-frame (looking to drop some weight by using aluminum) but neither option worked out so it looks as though those two (OEM) bits will stay.... 
I keep hoping for a set of Ti axles or a lightweight gas tank (Al or carbon) to get posted on eBay..... I hope to get it down to 400 lb wet (should be very close now)....
P.S. RC51 cluster weighs just slightly over half a pound less than stock dials (not the reason for the change, but a nice added benefit).
I keep hoping for a set of Ti axles or a lightweight gas tank (Al or carbon) to get posted on eBay..... I hope to get it down to 400 lb wet (should be very close now)....P.S. RC51 cluster weighs just slightly over half a pound less than stock dials (not the reason for the change, but a nice added benefit).
Last edited by mikstr; 01-15-2011 at 08:26 AM.
01-15-2011 | 08:28 AM
#4
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
So far he's leading... But I have a plan to catch up...
01-15-2011 | 08:32 AM
#5
Thread Starter
Senior Member
MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
Not sure I am leading Markus as your "OEM factor" is quite low too. Not a competition, I see it more as two great minds (ok, maybe not great minds, how about obsessively compulsive types, lol) having fun down quasi-parallel paths
BTW, thanks again for the help with the cluster re-wiring, everything went very smoothly all thanks to you
BTW, thanks again for the help with the cluster re-wiring, everything went very smoothly all thanks to you
Last edited by mikstr; 01-15-2011 at 08:37 AM.
01-15-2011 | 10:48 AM
#7
Thread Starter
Senior Member
MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
Two reasons:
i) I welded a CBR900RR brace to the swingarm so can no longer fit a VTR hugger
ii) I like the uncluttered look of having the chain open
01-15-2011 | 03:16 PM
#10
Senior Member
SuperBike
Joined: Aug 2009
Posts: 1,978
From: thorold ontario
thats a pretty sweet mod list you have planned. mine includes some new oil and maybe a re working of the fiberglass on my tail, and thats it 
you know you could buy a different bike, ducati to maintain a twin like sound, and stamp your vin to it and that would put you ahead of marcus
you know you could buy a different bike, ducati to maintain a twin like sound, and stamp your vin to it and that would put you ahead of marcus
01-15-2011 | 04:55 PM
#11
Senior Member
SuperBike
Joined: Jan 2007
Posts: 2,167
Mikstr, see red below
The big piece (engine rebuild) mostly out of the way, I am now turning my attention to a few other items as the bike lies dormant for the winter:
- instrument cluster: changed over the stock analog dials to a digital unit from RC51 (done!)
- gas cap: replaced the screw-type racing gas cap with a RCM billet piece (see pic)
- hugger: bought a hugger from Airtech (see pic; wanted one with no chain guard, only one I found was this one), will need paint (black) Do you know who has a hugger that fits the OE swingarm but has better rearward protection with & without an integral chain guard? I've looked but...
- MCs: replacing the OEM clutch and NIssin 19x18 brake radial with a set of OEM Ducati Monster 1100 Brembos. The main reason for the change is that the Brembo is a 19x16, which should give me added leverage and feel at the lever. I picked up a set of dark blue Pazzo levers to go along with the new master (will be parting with the existing bits shortly). I also got a good deal on a Discacciati billet 16x19 brake radial which I may try (matched to SP-2 calipers) if this is set-up does not give me the results I want. Otherwise, the Disca and SP-2 will be on the market (watch for them!) I also have the F4i calipers matched to a RVT SP1 19mm MC and am not happy with the feel even though the F4i calipers are the same as the RVT the F4i MC is smaller. Thus I know I could go to the F4i 5/8” (15.87mm) MC, as I'd also like better feel (and leverage) though would prefer a radial MC. What do U think? Let me know what your selling but I'm not sure it would be what I want anyway.
- calipers: replacing my existing (98-99) 900RR front and OEM rear with a set from an F4i (same units, just all black, it's an aesthetic thing; existing units to be sold shortly)
- rearsets: will be installing the K&T rearsets I bought from Beau (captainchaos)
- windscreen: installing a "cool blue" iridium double-bubble Powerbronze unit
- exhaust: repacking Akra cans (bought a set of dB killers too, which I will surely try at some point; cops around here are starting to monitor non-OEM exhausts....)
What R U repacking with? I went to ceramic batt years ago over fiberglass but also use a base of stainless steel wool.
- airbox: sent my recent (post-rebuild) dyno charts to Roger Ditchfield who stated that my results are not as good as they could be, feels the stock airbox is choking the engine, so I will trying to run a lid-less set-up (have a spare box I can cut up). He recommended I run a K&N filter and gave me the proper jetting specs to run (all jets in hand and ready to install). The improved breathing should land me a few extra lb-ft and hp... Will likely be parting with my almost-new BMC street filter shortly too.
- tires: just had the rear tire replaced with a Power Pure 190/55 (my PVM rim is a 6-incher), will also be getting the front replaced with a matching Pure. Front tire valves will be replaced with an aluminum 83-degree red anodized unit (as on rear)
- miscellaneous: blue titanium swingarm pivot bolt, various other Ti bolts and nuts (found a good supplier of relatively inexpensive Ti)
and that's it for now. As you can see, I will parting with a few nice bits in teh coming weeks if anyone is interested. Looking forward to getting it all done and out on the road
- instrument cluster: changed over the stock analog dials to a digital unit from RC51 (done!)
- gas cap: replaced the screw-type racing gas cap with a RCM billet piece (see pic)
- hugger: bought a hugger from Airtech (see pic; wanted one with no chain guard, only one I found was this one), will need paint (black) Do you know who has a hugger that fits the OE swingarm but has better rearward protection with & without an integral chain guard? I've looked but...
- MCs: replacing the OEM clutch and NIssin 19x18 brake radial with a set of OEM Ducati Monster 1100 Brembos. The main reason for the change is that the Brembo is a 19x16, which should give me added leverage and feel at the lever. I picked up a set of dark blue Pazzo levers to go along with the new master (will be parting with the existing bits shortly). I also got a good deal on a Discacciati billet 16x19 brake radial which I may try (matched to SP-2 calipers) if this is set-up does not give me the results I want. Otherwise, the Disca and SP-2 will be on the market (watch for them!) I also have the F4i calipers matched to a RVT SP1 19mm MC and am not happy with the feel even though the F4i calipers are the same as the RVT the F4i MC is smaller. Thus I know I could go to the F4i 5/8” (15.87mm) MC, as I'd also like better feel (and leverage) though would prefer a radial MC. What do U think? Let me know what your selling but I'm not sure it would be what I want anyway.
- calipers: replacing my existing (98-99) 900RR front and OEM rear with a set from an F4i (same units, just all black, it's an aesthetic thing; existing units to be sold shortly)
- rearsets: will be installing the K&T rearsets I bought from Beau (captainchaos)
- windscreen: installing a "cool blue" iridium double-bubble Powerbronze unit
- exhaust: repacking Akra cans (bought a set of dB killers too, which I will surely try at some point; cops around here are starting to monitor non-OEM exhausts....)
What R U repacking with? I went to ceramic batt years ago over fiberglass but also use a base of stainless steel wool.
- airbox: sent my recent (post-rebuild) dyno charts to Roger Ditchfield who stated that my results are not as good as they could be, feels the stock airbox is choking the engine, so I will trying to run a lid-less set-up (have a spare box I can cut up). He recommended I run a K&N filter and gave me the proper jetting specs to run (all jets in hand and ready to install). The improved breathing should land me a few extra lb-ft and hp...
Will likely be parting with my almost-new BMC street filter shortly too. - tires: just had the rear tire replaced with a Power Pure 190/55 (my PVM rim is a 6-incher), will also be getting the front replaced with a matching Pure. Front tire valves will be replaced with an aluminum 83-degree red anodized unit (as on rear)
- miscellaneous: blue titanium swingarm pivot bolt, various other Ti bolts and nuts (found a good supplier of relatively inexpensive Ti)
and that's it for now. As you can see, I will parting with a few nice bits in teh coming weeks if anyone is interested. Looking forward to getting it all done and out on the road
Last edited by skokievtr; 01-15-2011 at 05:00 PM.
01-15-2011 | 06:11 PM
#12
Thread Starter
Senior Member
MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
can't really be of much help when it comes to the hugger. I had a Puig before but parted with it as it made the rear look too bulky IMO (I find most hugger do this). I found exactly what I wanted.
As for the MC, the 19mm master will definitely give you a firm lever and require a lot of effort. The smaller F4i will require quite a bit more lever travel but, on the positive side, but require less effort and provide more feel. I will be parting with my Nissin radial MC (19x18; 19 mm piston with 18mm fulcrum distance). It works extremely well and 19x18 seems to be the most popular choice with most riders (for Brembo aftermarket radial buyers anyhow). This set-up works very well with the F4i calipers (is liked by those with SP-2 calipers too, though it would give a firmer lever there due to the smaller caliper pistons). I like a lighter effort with lots of feel (got spoiled from my ride on a Duc 1098S I guess, which uses a 19x16 master and 34/34 caliper pistons) so this is why I am opting for the OEM Duc Brembo. The 34/32 pistons in the F4i calipers will make the lever just slightly firmer but it's the best I can do with my budget. As I stated earlier, I also have a Discacciati 16x19 I could try if that doesn't give me the result I want.
AS for the re-packing material, I looked at buying the Two Brothers kit (roll of packing) but decided to get the proper Akra kit (everything is nicely stuffed inside a "sock" and you just slide it in). More $$$$ but idiot-proof
As for the MC, the 19mm master will definitely give you a firm lever and require a lot of effort. The smaller F4i will require quite a bit more lever travel but, on the positive side, but require less effort and provide more feel. I will be parting with my Nissin radial MC (19x18; 19 mm piston with 18mm fulcrum distance). It works extremely well and 19x18 seems to be the most popular choice with most riders (for Brembo aftermarket radial buyers anyhow). This set-up works very well with the F4i calipers (is liked by those with SP-2 calipers too, though it would give a firmer lever there due to the smaller caliper pistons). I like a lighter effort with lots of feel (got spoiled from my ride on a Duc 1098S I guess, which uses a 19x16 master and 34/34 caliper pistons) so this is why I am opting for the OEM Duc Brembo. The 34/32 pistons in the F4i calipers will make the lever just slightly firmer but it's the best I can do with my budget. As I stated earlier, I also have a Discacciati 16x19 I could try if that doesn't give me the result I want.
AS for the re-packing material, I looked at buying the Two Brothers kit (roll of packing) but decided to get the proper Akra kit (everything is nicely stuffed inside a "sock" and you just slide it in). More $$$$ but idiot-proof
01-16-2011 | 11:21 AM
#13
Senior Member
SuperBike
Joined: Jan 2007
Posts: 2,167
Part 1 - Master Cylinder Selection
Mikster, with all the opinions out there regarding mater cylinder selection, I offer the following for consideration.
01-16-11: “Author’s” (“SkokieVTR”) comments are in red
Refer to: http://www.oppracing.com/pages/articles_brembo_master_cylinders/
Example: 19x16 Billet Non-Folding Radial Brake Master Cylinder
19x16: This specification indicates two values. The first value is the diameter (ie. bore) of the cylinder in millimeters - it is usually 16mm or 19mm. In this case, the diameter is 19mm. The second value is the inter-axis (ie. distance) between the lever's pivot point and the plunger that pushes into the cylinder - it is usually 16mm, 18mm or 20mm. In this case, it's 16mm.
Now that we know what the numbers are, let's figure out what they mean in terms of braking performance. When you are selecting a master, you need to understand that these values trade-off braking sensitivity and braking power.
For the cylinder diameter, as that value increases, you increase your braking power because more square mm of same viscosity brake fluid is being compressed into presumably the same size orifice leading to the same diameter brake line to identical sets of 4-piston brake calipers. As you increase the diameter, you increase your cylinder size and increase the volume of brake fluid that you have to compress given the same length of piston stroke. This creates a dampening effect that allows you to better modulate the amount of brake pressure. Wrong, first because the correct word for this questionable rationale is “ damping”. As a general rule of thumb, you would use a 16xXX for a single caliper set-up and 19xXX for a dual caliper set-up. Of course, there are always exceptions - for example, the stock master cylinder for Yamaha R1's and R6's (which are made by Brembo) use a 16xXX set-up, despite the fact that they have dual front calipers.
For the inter-axis value, as that value increases (ie. the distance gets longer), you are decreasing your sensitivity and increasing your brake power. I don't want to get into the technical aspect or into the physics of it...that's not the goal of this article. If you feel like you need to know more, I would recommend you search Google or How Stuff Works This is a “cop-out” which I will rectify. In a general comparison between a 19x18 and 19x20 configuration (the most common configurations for sportbikes), a 19x18 has more feel but has a little more lever travel than the 19x20. By this rationale a 19 x 16 master cylinder will have a comparable increase in “feel” & lever travel as the 19x18 does when compared to the 19x20 (comparable changes in “mechanical advantage” ratios). A 19x20 configuration has more braking power and requires less distance to completely pull in the lever. This statement requires a proper explanation (proof of rationale), as follows:
Ultimately, the optimal configuration is up to you. Brembo recommends the 19x18 configuration for racers and the 19x20 configuration for street riders. In terms of real world examples, the billet master cylinder using in MotoGP is a 19x18 while the master cylinder includes with the Brembo High Performance street kits is a 19x20.
If the two prior sentences are true, then less feel and lever travel is better for street riders. This does not hold true. First a definition of “feel” is required before we go further. “Feel” is the ability to sense through your fingers the effect the force you are exerting on the brake fluid being compressed through the same size orifice in comparison to the braking force on the rotating wheel further compared to the increase in g-force on the pilot’s equilibrium; i.e., pilot’s measure (sense) of the rate of reduction of speed. In my opinion more feel at the expense of increased lever travel (amount of lever movement) is preferred for street riders because brake fade (caused by the reduction in viscosity & expansion of the brake fluid due to heat transfer as well as brake pad friction loss on the rotor) which further adds to the lever travel normally does not occur as much and/or as often as it can on a race track. On a race track the pilot has less distractions than a street rider and can thus better anticipate and compensate for increasing lever travel induced by “fade” with the quick-click or left-hand remote lever position adjusters.
01-16-11: “Author’s” (“SkokieVTR”) comments are in red
Refer to: http://www.oppracing.com/pages/articles_brembo_master_cylinders/
Example: 19x16 Billet Non-Folding Radial Brake Master Cylinder
19x16: This specification indicates two values. The first value is the diameter (ie. bore) of the cylinder in millimeters - it is usually 16mm or 19mm. In this case, the diameter is 19mm. The second value is the inter-axis (ie. distance) between the lever's pivot point and the plunger that pushes into the cylinder - it is usually 16mm, 18mm or 20mm. In this case, it's 16mm.
Now that we know what the numbers are, let's figure out what they mean in terms of braking performance. When you are selecting a master, you need to understand that these values trade-off braking sensitivity and braking power.
For the cylinder diameter, as that value increases, you increase your braking power because more square mm of same viscosity brake fluid is being compressed into presumably the same size orifice leading to the same diameter brake line to identical sets of 4-piston brake calipers. As you increase the diameter, you increase your cylinder size and increase the volume of brake fluid that you have to compress given the same length of piston stroke. This creates a dampening effect that allows you to better modulate the amount of brake pressure. Wrong, first because the correct word for this questionable rationale is “ damping”. As a general rule of thumb, you would use a 16xXX for a single caliper set-up and 19xXX for a dual caliper set-up. Of course, there are always exceptions - for example, the stock master cylinder for Yamaha R1's and R6's (which are made by Brembo) use a 16xXX set-up, despite the fact that they have dual front calipers.
For the inter-axis value, as that value increases (ie. the distance gets longer), you are decreasing your sensitivity and increasing your brake power. I don't want to get into the technical aspect or into the physics of it...that's not the goal of this article. If you feel like you need to know more, I would recommend you search Google or How Stuff Works This is a “cop-out” which I will rectify. In a general comparison between a 19x18 and 19x20 configuration (the most common configurations for sportbikes), a 19x18 has more feel but has a little more lever travel than the 19x20. By this rationale a 19 x 16 master cylinder will have a comparable increase in “feel” & lever travel as the 19x18 does when compared to the 19x20 (comparable changes in “mechanical advantage” ratios). A 19x20 configuration has more braking power and requires less distance to completely pull in the lever. This statement requires a proper explanation (proof of rationale), as follows:
Ultimately, the optimal configuration is up to you. Brembo recommends the 19x18 configuration for racers and the 19x20 configuration for street riders. In terms of real world examples, the billet master cylinder using in MotoGP is a 19x18 while the master cylinder includes with the Brembo High Performance street kits is a 19x20.
If the two prior sentences are true, then less feel and lever travel is better for street riders. This does not hold true. First a definition of “feel” is required before we go further. “Feel” is the ability to sense through your fingers the effect the force you are exerting on the brake fluid being compressed through the same size orifice in comparison to the braking force on the rotating wheel further compared to the increase in g-force on the pilot’s equilibrium; i.e., pilot’s measure (sense) of the rate of reduction of speed. In my opinion more feel at the expense of increased lever travel (amount of lever movement) is preferred for street riders because brake fade (caused by the reduction in viscosity & expansion of the brake fluid due to heat transfer as well as brake pad friction loss on the rotor) which further adds to the lever travel normally does not occur as much and/or as often as it can on a race track. On a race track the pilot has less distractions than a street rider and can thus better anticipate and compensate for increasing lever travel induced by “fade” with the quick-click or left-hand remote lever position adjusters.
01-16-2011 | 11:22 AM
#14
Senior Member
SuperBike
Joined: Jan 2007
Posts: 2,167
Part 2 - Master Cylinder Selection
Refer to: http://www.600rr.net/vb/showthread.php?p=2708482
NEW BREMBO 19 RCS RADIAL BRAKE MASTER CYLINDER (OFFICIAL BREMBO PRESS RELEASE)
The Brembo radial master cylinder has effectively revolutionized motorcycle braking systems over the past ten years. Designed originally for use on Racing machines, it has become more and more popular over time for Super Sport, and even Naked bikes, while retaining the identity of an out-and-out racing component, still used today in MotoGP competition.
Today, bike enthusiasts everywhere can upgrade the braking system on their machines at a stroke, simply by replacing the production master cylinder with a Brembo radial, confident of the top-flight performance associated with many years’ experience acquired by the company in designing and engineering braking systems.
Why radial? The definition indicates a configuration whereby force can be transmitted to the piston in phase with the force applied by hand to the lever, eliminating the friction that would be generated if these forces were separated. In other words, the effort exerted by hand on the lever and the force applied by the lever to the piston are both generated in the same direction radially relative to the point where the cylinder is anchored, i.e. the handlebar. With this type of construction, the master cylinder can be designed with the focus on optimizing hydraulic and mechanical ratios, and consequently on improving its performance. This means that the force applied to the lever can be converted entirely into powerful, dependable and precise braking action.
For twin-disc systems; there are currently two models of Brembo radial master cylinder available: 19x18 and 19x20. The choice between the two models will be based essentially on the feel that the rider is able to get from the two solutions.
The 19x18 cylinder has better modulation, given its marginally longer operating travel when compared to the 19x20, which on the other hand offers a slightly quicker response. As a general rule, the 19x18 is recommended for bikes with 4-piston calipers (diameters 32/36, 34/34 and 30/34), whereas the 19x20 is more suitable for other calipers such as the Brembo High Performance (HP) Calipers.
Brembo experience favours 19x18 for track, and 19x20 for street. Today, after 10 years as a brand leader, this legendary product has been updated with a number of significant new engineering features, all derived from MotoGP, and is now marketed as the new Racing radial brake master cylinder.
Brembo conversely should also have stated that shorter lever travel = “quicker response” and requires greater force to be applied to the same point on the lever. This “lever pressure point” must be approximated based on an average determined by a survey of where a representative sampling of an appropriate number of pilot’s fingers cover a varying length along the width of the lever, along with how many fingers and how much force (torque) each of their fingers exert on the lever. So for comparison purposes a standard “lever pressure point” must be selected closest to where the highest force on average is exerted on the lever (based on an average of a point on the lever where the strongest fingers contact a given length lever), and this “lever pressure point” used to determine the distance to the “lever-to-piston rod pivot point” (fulcrum); i.e., to determine the length of the “lever arm”. Keep in mind that the fulcrum is in-line with the rod that actuates and connects to the piston and its direction of travel (stroke). Also understand that the “lever arm” is the length of lever on the opposite side of the fulcrum from the length of the lever that terminates at the “lever pivot point” (i.e., the “reaction point” in this “moment diagram”). So accordingly, a longer lever stroke = “better modulation” because less force is needed to be applied to the lever (which will be explained below) Consequently, Brembo’s rationale should have included that along with “better modulation” a shorter “inter-axis distance” also gives slower response; which further contributes to better control (modulate) braking force (torque). So why is the amount of force actually reduced by a shorter “inter-axis distance” (i.e., inter-axis = distance between the lever's pivot point and the plunger that pushes into the cylinder or “lever-to-piston rod pivot point”)? It should be understood that the muscles operating the fingers cannot exert as linear an amount of force at higher levels of effort; which plays a part in providing increased sensitivity or “feel”. Therefore, more lever travel also makes it easier to modulate control. The reason a lower level of force is afforded by a shorter “inter-axis distance” over the consequential greater lever travel produces the same amount of “work” (“reaction”) is due to the effect of the longer “lever arm”; given the proper angle of “attack” on the piston rod pivot (fulcrum) is maintained by adjusting the position of the lever in relation to the geometry of the pilot’s hand. In other words, based on the same overall lever length and “pivot point” location, a shorter “inter-axis” distance creates a longer “lever arm”, and a longer lever arm will result in an equal amount work with application of a lesser amount of force (torque) in what is a simple load calculation. The key to understanding this “mechanical advantage” analysis is how the location of the fulcrum determines “lever arm” and “reaction arm” lengths along a set overall length lever. The “reaction arm” is the portion of the lever opposite the “lever arm” as separated by the fulcrum. Again, the greater (longer) the “lever arm”, the less force is required to produce the same amount of work (reaction on the piston). Visa-vie the result of a shorter lever arm as created by a longer “inter-axis” distance requires more force (torque) to produce a comparable amount of work; i.e., a shorter lever arm length = greater force required to move the same size piston given the same viscosity brake fluid is passing through the same size orifice. This is basic mechanical engineering and fluid power mechanics. I simply don’t understand Brembo’s recommendations as to selection of “inter-axis” distance for the road and track given the same size and type brake lines and calipers. The total surface area in square millimeters of the 4-piston caliper diameters included in Brembo’s recommendation for a 19x18 master cylinder ranges between 402.5 square millimeters and 427 square millimeters; with the “leading” (opposed) set of pistons being the smaller diameter pistons of the two piston sizes indicated.
Final note: The reason that lever arm travel increases with shorter inter-axis distance is because the longer resulting lever arm must move farther given the same piston stroke length and direction; i.e., based on simple geometry. Also, the rationale is based on the identical master cylinder being utilized with only the “inter-axis” distance varying with overall lever length (and stiffness) remaining constant. Bear in mind the same effects can be achieved by increasing or decreasing piston diameter (and length of piston) stroke as by varying “inter-axis” distance; similarly, the same physics apply to non-radial brake master cylinders in regard to mechanical advantage geometry, piston diameter and stroke, and lever arm and reaction arm lengths. Furthermore, the “bling factor” versus true improved performance advantage of radial mounted calipers is deceiving given that all available “radial calipers” are not truly radial in that the mounting bolts are actually offset from the rotors and thus the calipers and their mounting points are still subject to “twisting” as are non-radial caliper assemblies. The purported increased performance (and possible reduced weight) of the plethora of “monobloc” calipers and billet master cylinders has as much to do with their increased stiffness and use of better materials and consequential tighter tolerances as with any inherent “radial design” advantages; more so for racing than street use. Many radial “set-ups” have been judged to be inferior to less costly conventional non-radial assemblies.
Consequently, I may go instead to a smaller diameter piston, say from the RVT (RC51 / VTR1000) SP1’s 19 mm to the RVT SP2 master cylinder’s 11/16” (17.4625 mm) piston diameter to achieve better feel and maybe realize more “bang for my buck”.
NEW BREMBO 19 RCS RADIAL BRAKE MASTER CYLINDER (OFFICIAL BREMBO PRESS RELEASE)
The Brembo radial master cylinder has effectively revolutionized motorcycle braking systems over the past ten years. Designed originally for use on Racing machines, it has become more and more popular over time for Super Sport, and even Naked bikes, while retaining the identity of an out-and-out racing component, still used today in MotoGP competition.
Today, bike enthusiasts everywhere can upgrade the braking system on their machines at a stroke, simply by replacing the production master cylinder with a Brembo radial, confident of the top-flight performance associated with many years’ experience acquired by the company in designing and engineering braking systems.
Why radial? The definition indicates a configuration whereby force can be transmitted to the piston in phase with the force applied by hand to the lever, eliminating the friction that would be generated if these forces were separated. In other words, the effort exerted by hand on the lever and the force applied by the lever to the piston are both generated in the same direction radially relative to the point where the cylinder is anchored, i.e. the handlebar. With this type of construction, the master cylinder can be designed with the focus on optimizing hydraulic and mechanical ratios, and consequently on improving its performance. This means that the force applied to the lever can be converted entirely into powerful, dependable and precise braking action.
For twin-disc systems; there are currently two models of Brembo radial master cylinder available: 19x18 and 19x20. The choice between the two models will be based essentially on the feel that the rider is able to get from the two solutions.
The 19x18 cylinder has better modulation, given its marginally longer operating travel when compared to the 19x20, which on the other hand offers a slightly quicker response. As a general rule, the 19x18 is recommended for bikes with 4-piston calipers (diameters 32/36, 34/34 and 30/34), whereas the 19x20 is more suitable for other calipers such as the Brembo High Performance (HP) Calipers.
Brembo experience favours 19x18 for track, and 19x20 for street. Today, after 10 years as a brand leader, this legendary product has been updated with a number of significant new engineering features, all derived from MotoGP, and is now marketed as the new Racing radial brake master cylinder.
Brembo conversely should also have stated that shorter lever travel = “quicker response” and requires greater force to be applied to the same point on the lever. This “lever pressure point” must be approximated based on an average determined by a survey of where a representative sampling of an appropriate number of pilot’s fingers cover a varying length along the width of the lever, along with how many fingers and how much force (torque) each of their fingers exert on the lever. So for comparison purposes a standard “lever pressure point” must be selected closest to where the highest force on average is exerted on the lever (based on an average of a point on the lever where the strongest fingers contact a given length lever), and this “lever pressure point” used to determine the distance to the “lever-to-piston rod pivot point” (fulcrum); i.e., to determine the length of the “lever arm”. Keep in mind that the fulcrum is in-line with the rod that actuates and connects to the piston and its direction of travel (stroke). Also understand that the “lever arm” is the length of lever on the opposite side of the fulcrum from the length of the lever that terminates at the “lever pivot point” (i.e., the “reaction point” in this “moment diagram”). So accordingly, a longer lever stroke = “better modulation” because less force is needed to be applied to the lever (which will be explained below) Consequently, Brembo’s rationale should have included that along with “better modulation” a shorter “inter-axis distance” also gives slower response; which further contributes to better control (modulate) braking force (torque). So why is the amount of force actually reduced by a shorter “inter-axis distance” (i.e., inter-axis = distance between the lever's pivot point and the plunger that pushes into the cylinder or “lever-to-piston rod pivot point”)? It should be understood that the muscles operating the fingers cannot exert as linear an amount of force at higher levels of effort; which plays a part in providing increased sensitivity or “feel”. Therefore, more lever travel also makes it easier to modulate control. The reason a lower level of force is afforded by a shorter “inter-axis distance” over the consequential greater lever travel produces the same amount of “work” (“reaction”) is due to the effect of the longer “lever arm”; given the proper angle of “attack” on the piston rod pivot (fulcrum) is maintained by adjusting the position of the lever in relation to the geometry of the pilot’s hand. In other words, based on the same overall lever length and “pivot point” location, a shorter “inter-axis” distance creates a longer “lever arm”, and a longer lever arm will result in an equal amount work with application of a lesser amount of force (torque) in what is a simple load calculation. The key to understanding this “mechanical advantage” analysis is how the location of the fulcrum determines “lever arm” and “reaction arm” lengths along a set overall length lever. The “reaction arm” is the portion of the lever opposite the “lever arm” as separated by the fulcrum. Again, the greater (longer) the “lever arm”, the less force is required to produce the same amount of work (reaction on the piston). Visa-vie the result of a shorter lever arm as created by a longer “inter-axis” distance requires more force (torque) to produce a comparable amount of work; i.e., a shorter lever arm length = greater force required to move the same size piston given the same viscosity brake fluid is passing through the same size orifice. This is basic mechanical engineering and fluid power mechanics. I simply don’t understand Brembo’s recommendations as to selection of “inter-axis” distance for the road and track given the same size and type brake lines and calipers. The total surface area in square millimeters of the 4-piston caliper diameters included in Brembo’s recommendation for a 19x18 master cylinder ranges between 402.5 square millimeters and 427 square millimeters; with the “leading” (opposed) set of pistons being the smaller diameter pistons of the two piston sizes indicated.
Final note: The reason that lever arm travel increases with shorter inter-axis distance is because the longer resulting lever arm must move farther given the same piston stroke length and direction; i.e., based on simple geometry. Also, the rationale is based on the identical master cylinder being utilized with only the “inter-axis” distance varying with overall lever length (and stiffness) remaining constant. Bear in mind the same effects can be achieved by increasing or decreasing piston diameter (and length of piston) stroke as by varying “inter-axis” distance; similarly, the same physics apply to non-radial brake master cylinders in regard to mechanical advantage geometry, piston diameter and stroke, and lever arm and reaction arm lengths. Furthermore, the “bling factor” versus true improved performance advantage of radial mounted calipers is deceiving given that all available “radial calipers” are not truly radial in that the mounting bolts are actually offset from the rotors and thus the calipers and their mounting points are still subject to “twisting” as are non-radial caliper assemblies. The purported increased performance (and possible reduced weight) of the plethora of “monobloc” calipers and billet master cylinders has as much to do with their increased stiffness and use of better materials and consequential tighter tolerances as with any inherent “radial design” advantages; more so for racing than street use. Many radial “set-ups” have been judged to be inferior to less costly conventional non-radial assemblies.
Consequently, I may go instead to a smaller diameter piston, say from the RVT (RC51 / VTR1000) SP1’s 19 mm to the RVT SP2 master cylinder’s 11/16” (17.4625 mm) piston diameter to achieve better feel and maybe realize more “bang for my buck”.
Last edited by skokievtr; 01-16-2011 at 11:26 AM.
01-16-2011 | 11:48 AM
#15
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Joined: Apr 2010
Posts: 219
From: Prague - Czech
what I know if master is 19x16 that means short lever travel and agressive stopping power, continously 19x20 is longer travel and better control. Race riders are recommended for shorter because of heating of brakes when travel on 19x20 would be too long when race hard.
01-16-2011 | 12:19 PM
#16
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MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
you have it backwards Stephan. A 19x20 has shorter travel but requires more effort at the lever than a 19x16 (which, by comparison, has longer travel but requires less effort to squeeze for the same amount of braking force).
01-16-2011 | 01:37 PM
#17
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SuperBike
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Posts: 2,167
01-16-2011 | 05:40 PM
#19
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SuperBike
Joined: Aug 2009
Posts: 1,978
From: thorold ontario
most guys i know that track bikes tend to prefer a 19x18 brembo setup,even on their street bikes its what they choose to run. ive got a 19x20 that im going to throw onto my track bike. see how i like it, without going to a bigger brake setup on my kawi ill see if the 19x20 will compensate a little.
01-16-2011 | 06:04 PM
#20
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Posts: 2,167
01-17-2011 | 02:34 AM
#21
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Joined: Apr 2010
Posts: 219
From: Prague - Czech
skokievtr:
read just now, but could be little bit shorter and without red imo, no offense
Just my comment to your choice. As I ride full SP2 brake setup, I can say brake master works just as I like, proper travel and great feel. For bigger pistons of your brake, I´d expect this master has longer lever travel.
Second question is what is the original pivot of SP1 master, maybe if you go with 19x18 or 19x16 it would be better than smaller piston.
Next thing is brake pads used, changes the feeling of the brakes as well, maybe change on this would be enough.
But it´s just a theory and depends on personal preferrences.
Sorry for off-topic, this thread is not only about brakes.
read just now, but could be little bit shorter and without red imo, no offense
Just my comment to your choice. As I ride full SP2 brake setup, I can say brake master works just as I like, proper travel and great feel. For bigger pistons of your brake, I´d expect this master has longer lever travel.
Second question is what is the original pivot of SP1 master, maybe if you go with 19x18 or 19x16 it would be better than smaller piston.
Next thing is brake pads used, changes the feeling of the brakes as well, maybe change on this would be enough.
But it´s just a theory and depends on personal preferrences.
Sorry for off-topic, this thread is not only about brakes.
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Mike996
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