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Post by JonW on Jun 2, 2023 0:28:19 GMT 1
midlifecrisisrd : Tokico 6 pots and Fazer 14mm master? Let me know the piston sizes and I'll do the calculation, just for interests sake. FYI, 6 pots come in two types, either all 6 of the piston sizes are 27mm or there is a type where they have 4x27mm pistons and 2x24mm pistons in each caliper.
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Post by cb250g5 on Jun 2, 2023 8:07:19 GMT 1
And because I'm bored I decided to rate your brakes. No offense intended. cb250g5 : Single blue spot, TDR master. Poor overall ratio, I would expect it to feel wooden and have very little power, but that might be compensated a little by the large disc you have fitted. It might be worth trying a 11mm master from a YBR or YZF 125. You couldn't be more wrong. Not masses of lever movement, but one finger braking, and more than enough power to do a stoppie, should such a thing be required. To be 100% correct I have an aluminium pistoned gold spot, not a blue, but pretty much the same brake.
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Post by midlifecrisisrd on Jun 2, 2023 8:54:27 GMT 1
Bugger ā¹ļø, after getting on Google to fine out I hadn't looked over the page and jonw had already posted š¤£
As he says some calipers are 6 x 27mm and some are 4 x 27 and 2 x 24mm
No idea what's on mine š¤
Steve
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Post by crogthomas on Jun 2, 2023 11:19:00 GMT 1
And because I'm bored I decided to rate your brakes. No offense intended. cb250g5 : Single blue spot, TDR master. Poor overall ratio, I would expect it to feel wooden and have very little power, but that might be compensated a little by the large disc you have fitted. It might be worth trying a 11mm master from a YBR or YZF 125. You couldn't be more wrong. Not masses of lever movement, but one finger braking, and more than enough power to do a stoppie, should such a thing be required. To be 100% correct I have an aluminium pistoned gold spot, not a blue, but pretty much the same brake. Interesting. Leaving my geeky spreadsheet aside, the blue/gold spots were originally used with a 14mm master for both calipers. When using a 14mm master for just one caliper, I would expect to have half the braking power. I wonder if the lever ratios were changed at the same time? Can you measure the TDR master?
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Post by cb250g5 on Jun 2, 2023 12:59:08 GMT 1
You couldn't be more wrong. Not masses of lever movement, but one finger braking, and more than enough power to do a stoppie, should such a thing be required. To be 100% correct I have an aluminium pistoned gold spot, not a blue, but pretty much the same brake. Interesting. Leaving my geeky spreadsheet aside, the blue/gold spots were originally used with a 14mm master for both calipers. When using a 14mm master for just one caliper, I would expect to have half the braking power. I wonder if the lever ratios were changed at the same time? Can you measure the TDR master? Not without taking it apart. I'll take a look over the weekend, see if it has anything embossed on it. I've had a variety of masters used with single colour-spot calipers on various bikes, always with 320mm disks, and this is the best setup I've found. I quite liked a suzuki one, with a remote reservoir, but the reservoir leaked a bit & meant I couldn't easily fit mirrors, so I binned that off. I still have my SRX 400 with the same disk and a blue spot, using the original master, and that works well, it's as light as a feather anyway, so well overbraked. My TDR used a silver spot caliper and the TDR master, and again it was fine, that had a Tokico 4 pot on it when I got it I think.
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Post by crogthomas on Jun 2, 2023 21:58:12 GMT 1
Not without taking it apart. I'll take a look over the weekend, see if it has anything embossed on it. The bore diameter is normally embossed in the casting, but I'd also be interested to see work out the lever ratio. I'd need the distance from the pivot to the centre of the part which acts on the piston. 20230531_212548 by crogthomas, on Flickr Also the distance from the pivot to the middle finger whilst your hand in on the lever in the normal position. It's a bit variable due to the nature of er, nature, but a rough idea would be useful.
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Post by crogthomas on Jun 2, 2023 21:59:46 GMT 1
midlifecrisisrd : Tokico 6 pots and Fazer 14mm master? Let me know the piston sizes and I'll do the calculation, just for interests sake. FYI, 6 pots come in two types, either all 6 of the piston sizes are 27mm or there is a type where they have 4x27mm pistons and 2x24mm pistons in each caliper. Thanks. What would they have been from? Are the 27&24mm ones GSXR750 SRAD?
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Post by JonW on Jun 3, 2023 0:16:41 GMT 1
FYI, 6 pots come in two types, either all 6 of the piston sizes are 27mm or there is a type where they have 4x27mm pistons and 2x24mm pistons in each caliper. Thanks. What would they have been from? Are the 27&24mm ones GSXR750 SRAD? dunno, no one seems to have a definitive, but i guess its in the parts books? check the piston part nos?
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Post by midlifecrisisrd on Jun 3, 2023 13:06:41 GMT 1
FYI, 6 pots come in two types, either all 6 of the piston sizes are 27mm or there is a type where they have 4x27mm pistons and 2x24mm pistons in each caliper. Thanks. What would they have been from? Are the 27&24mm ones GSXR750 SRAD? I bought mine as GSXR1300 Busa calipers Parts list shows the seal kits as 8 larger 4 smaller so looks like the 27, 27, 24 type Steve
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Post by 4l04ever on Jun 4, 2023 14:58:22 GMT 1
I run a single Bluespot front caliper with a YBR125 11mm master cylinder. Great feel now.
Have gone from 5/8" to 14mm, then 1/2" now 11mm. Got better feel and less wooden each time.
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Post by oldelsieboy on Jun 4, 2023 16:59:32 GMT 1
The 14mm TDR m/c works just as well with this setup. OEB
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Post by abar121 on Jun 5, 2023 21:05:48 GMT 1
And because I'm bored I decided to rate your brakes. No offense intended. .. abar121 : Fazer 14mm master, Triumph T595 calipers. I would expect it to have a mushy lever feel, plenty of power mind you. Going back to a 5/8 master might improve the lever feel, but still give decent braking. It's certainly powerful and not at all mushy. Pretty solid at the level in fact. There are many other factors involved here, including the pads themselves. Which I must admit I have no clue about. The calipers were 2nd hand and had sintered pads already fitted with decent life left, so I've just run them after a pikey brake rebuild. Read: half a can of brake clean emptied.
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Post by JonW on Jun 6, 2023 0:20:18 GMT 1
Something Ive found over the years is that there defo is something more than just maths at work with brakes as there are other factors that mean that empirical data trumps the equations more often than not.
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Post by crogthomas on Jun 8, 2023 9:25:30 GMT 1
I'm of the opinion that nearly everything can be explained by maths, it's just that in this case we don't have all the required information. I suspect to properly characterise different brake setups we would need to know much more about them. Such as pad friction (as noted), disc sizes, wheel size, even total vehicle mass. Probably the best thing to do is to relate the lever force to deceleration. For example, the TZR250 and FJ1200 use basically the same brakes, but I suspect that they feel and perform very differently simply due to the mass of a fully loaded FJ1200 being close to twice that of the TZR. I concede that there will always be an element of personal preference to consider. Some people brake really hard all the time, whilst others will be gentle on the brakes, only using them hard in an emergency. The same brakes will feel very different to each rider. I think the simple table I created is still useful to be able to choose a master cylinder to get somewhere near what is needed. Plus it can tell you what sort of effect making a single change to the system will have, everything else being equal. If anyone finds it useful, I've updated it here with a few more combinations. RDbrakes by crogthomas, on Flickr
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Post by 4l04ever on Jun 8, 2023 20:14:55 GMT 1
It is tricky to put into numbers how much an OEM brake line can swell when under pressure. Braided lines don't have that issue though.
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Post by reedvalve on Jun 9, 2023 8:54:22 GMT 1
I've been pondering about doing something with the brakes on my 31K and saw this thread, tomtom1 description of the improvement sold it to me, and I ran off and ordered the 14mm master cylinder from Legend Motorcycles. When it arrived, it turns out they're not 14mm master cylinders but 12.7mm (1/2 "), see the photo of the markings on the underside. I messaged Dan at Legend Motorcycles querying it, his reply was "1/2" is for single disc. Im aware its 12.7mm but for whatever reason they call them 14mm or 1/2" cylinders." As murp says he uses a 1/2" on his 350 without excess lever travel then I'm going to fit it and give it a go, but beware if you're after a genuine 14mm bore master cylinder the one Legend sells as 14mm isn't, it is actually 12.7mm Chris
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Post by midlifecrisisrd on Jun 9, 2023 9:29:29 GMT 1
Typical legend š
I'd have sent it back as wrong item
You can't sell a 14mm and send a 12.7mm
Steve
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Post by JonW on Jun 9, 2023 9:31:55 GMT 1
Ahh... Legend... Sigh... Its just simple maths... 12.7mm is NOT 14mm. I say this as I read what you wrote and take it to mean that this is listed on ebay as 14mm and you got a 12.7. If so, you didnt get what was advertised if you 'bought a 14mm'. Send it back using ebay returns if you want a 14mm and not a 12.7. Find another supplier who actually sells a 14mm. You cant sell something as 14mm and when you get a query say, "1/2" is for single disc". That isnt the right answer! EDITED: I see Steve posted while I was writing with the same info.
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Post by dougw on Jun 9, 2023 9:54:27 GMT 1
I've been pondering about doing something with the brakes on my 31K and saw this thread, tomtom1 description of the improvement sold it to me, and I ran off and ordered the 14mm master cylinder from Legend Motorcycles. When it arrived, it turns out they're not 14mm master cylinders but 12.7mm (1/2 "), see the photo of the markings on the underside. I messaged Dan at Legend Motorcycles querying it, his reply was "1/2" is for single disc. Im aware its 12.7mm but for whatever reason they call them 14mm or 1/2" cylinders." As murp says he uses a 1/2" on his 350 without excess lever travel then I'm going to fit it and give it a go, but beware if you're after a genuine 14mm bore master cylinder the one Legend sells as 14mm isn't, it is actually 12.7mm Chris With standard LC callipers and braided lines I much prefer the 1/2 " master cylinder to the 14mm, having tried both new. Braided hoses do not increase braking power, only reduce lever travel as they don`t expand as much, enabling you to use a smaller diameter master cylinder and not have excessive lever travel.
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Post by reedvalve on Jun 9, 2023 11:16:54 GMT 1
Ahh... Legend... Sigh... Its just simple maths... 12.7mm is NOT 14mm. I say this as I read what you wrote and take it to mean that this is listed on ebay as 14mm and you got a 12.7. If so, you didnt get what was advertised if you 'bought a 14mm'. Send it back using ebay returns if you want a 14mm and not a 12.7. Find another supplier who actually sells a 14mm. You cant sell something as 14mm and when you get a query say, "1/2" is for single disc". That isnt the right answer! EDITED: I see Steve posted while I was writing with the same info.
I went for it thinking it was 14mm based on what the creator of the thread tomtom1 wrote about the braking improvement and no excess loss of lever travel. Turns out he has a 12.7mm master cylinder and not the 14mm one he thinks he has! Clearly in tomtom1 case he's very happy with the change and as both murp and dougw have confirmed they're also using 12.7mm with no problems I'm going to use it. My bike has braided hoses as well so that will also help keep lever travel to a minimum, as has been discussed.
I'm going to reply to Legend pointing out he might like to correct the description, be interesting to see if it gets changed.
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Post by elsiefan on Jun 9, 2023 13:00:24 GMT 1
Ahh... Legend... Sigh... Its just simple maths... 12.7mm is NOT 14mm. I say this as I read what you wrote and take it to mean that this is listed on ebay as 14mm and you got a 12.7. If so, you didnt get what was advertised if you 'bought a 14mm'. Send it back using ebay returns if you want a 14mm and not a 12.7. Find another supplier who actually sells a 14mm. You cant sell something as 14mm and when you get a query say, "1/2" is for single disc". That isnt the right answer! EDITED: I see Steve posted while I was writing with the same info.
I went for it thinking it was 14mm based on what the creator of the thread tomtom1 wrote about the braking improvement and no excess loss of lever travel. Turns out he has a 12.7mm master cylinder and not the 14mm one he thinks he has! Clearly in tomtom1 case he's very happy with the change and as both murp and dougw have confirmed they're also using 12.7mm with no problems I'm going to use it. My bike has braided hoses as well so that will also help keep lever travel to a minimum, as has been discussed.
I'm going to reply to Legend pointing out he might like to correct the description, be interesting to see if it gets changed.
Just checked the underside of my 'TDR250 14mm' MC and it also says 12.7! Hmmm š¤ It works well, however, and I'm very happy with the braking performance, there is more lever travel, but it's not a problem.
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Post by jon on Jun 9, 2023 13:32:19 GMT 1
Iām glad of the above posts. I was thinking of ordering one to replace my 1/2ā one. Would have been a complete waste of money.
Jon
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Post by oldelsieboy on Jun 9, 2023 13:42:20 GMT 1
Ahh... Legend... Sigh... Its just simple maths... 12.7mm is NOT 14mm. I say this as I read what you wrote and take it to mean that this is listed on ebay as 14mm and you got a 12.7. If so, you didnt get what was advertised if you 'bought a 14mm'. Send it back using ebay returns if you want a 14mm and not a 12.7. Find another supplier who actually sells a 14mm. You cant sell something as 14mm and when you get a query say, "1/2" is for single disc". That isnt the right answer! EDITED: I see Steve posted while I was writing with the same info.
I went for it thinking it was 14mm based on what the creator of the thread tomtom1 wrote about the braking improvement and no excess loss of lever travel. Turns out he has a 12.7mm master cylinder and not the 14mm one he thinks he has! Clearly in tomtom1 case he's very happy with the change and as both murp and dougw have confirmed they're also using 12.7mm with no problems I'm going to use it. My bike has braided hoses as well so that will also help keep lever travel to a minimum, as has been discussed.
I'm going to reply to Legend pointing out he might like to correct the description, be interesting to see if it gets changed.
Legend already know, I told them when I returned the one I bought from them a couple of months ago š OEB
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Post by JonW on Jun 9, 2023 13:42:49 GMT 1
Im glad people are happy with the fact its a 1/2", but geez, its not a 14mm which means its not as advertised. That's mental even for Legend.
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Post by JonW on Jun 9, 2023 13:50:40 GMT 1
I went for it thinking it was 14mm based on what the creator of the thread tomtom1 wrote about the braking improvement and no excess loss of lever travel. Turns out he has a 12.7mm master cylinder and not the 14mm one he thinks he has! Clearly in tomtom1 case he's very happy with the change and as both murp and dougw have confirmed they're also using 12.7mm with no problems I'm going to use it. My bike has braided hoses as well so that will also help keep lever travel to a minimum, as has been discussed. I'm going to reply to Legend pointing out he might like to correct the description, be interesting to see if it gets changed.
Legend already know, I told them when I returned the one I bought from them a couple of months ago š OEB So, at this point intentionally mis-selling this item then... Sigh.
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Post by Tobyjugs on Jun 9, 2023 15:10:11 GMT 1
In the past i have used an SZR master cylinder with standard with caliper and discs to good effect. I don't mind the original set up you just have to squeeze harder. The problem for me is jumping from a standard set up to a modified set up. It becomes all too easy to lock the front wheel.
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Post by elsiefan on Jun 9, 2023 15:44:50 GMT 1
Im glad people are happy with the fact its a 1/2", but geez, its not a 14mm which means its not as advertised. That's mental even for Legend. My original MC was in poor shape anyway, one of the screws had sheared off and it needed an overhaul, so a new one was on the cards and for the price it appeared a good deal. As it works and improves the braking, I'm sanguine about the bore size, though I agree that if you genuinely needed a 14mm bore, it's a rum do. Lesson learned!
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Post by jon on Jun 9, 2023 16:53:55 GMT 1
I went for it thinking it was 14mm based on what the creator of the thread tomtom1 wrote about the braking improvement and no excess loss of lever travel. Turns out he has a 12.7mm master cylinder and not the 14mm one he thinks he has! Clearly in tomtom1 case he's very happy with the change and as both murp and dougw have confirmed they're also using 12.7mm with no problems I'm going to use it. My bike has braided hoses as well so that will also help keep lever travel to a minimum, as has been discussed. I'm going to reply to Legend pointing out he might like to correct the description, be interesting to see if it gets changed.
Legend already know, I told them when I returned the one I bought from them a couple of months ago š OEB That does not surprise me in the slightest given their previous history. A real shame as some of their products were top draw. Jon
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Post by reedvalve on Jun 9, 2023 17:38:18 GMT 1
Just fitted the 12.7mm master cylinder and have been for a quick ride, bike has standard 31k calipers and braided hoses. Wow what a difference, wish I'd done this years ago. The brakes have gone from a solid lever with very little movement that required 4 fingers and had a wooden feel to 2 fingers and loads of feel and power. The lever is now squidgy like a modern bike and not rock solid (don't want to say spongy as that implies there's air in the system) and makes for nicer braking at lower manoeuvring speeds as well as hard braking. it does show up the poor forks more though!
The lever does travel more when you pull it when stationary, but doesn't come all the way back to the bar, it might be a bit disconcerting when you first fitted it and bleed the system if this was your only bike and point of reference, but if you have anything modern it's more typical of what you would be use to. In fact comparing it to my BMW K1300S it has less lever travel than the BM's stock Brembo set up.
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Post by steve63 on Jun 9, 2023 19:52:47 GMT 1
I just bought a Yamaha SR125 master cylinder today. It's 1/2" and I'm pretty sure it's the same as a 250LC one. I'm going to refurb it. It'll give me an option to try when I finally get the 350 finished.
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