So,
I have 2 rds running single yamaha calipers, one blue dot, one gold dot. In the quest to find that good lever feel, ive tried a bunch of different units, 12mm, 13mm , 10mm, 11mm.
from what -I- have found, the 11mm master from either a KX85 or YZ85 (nissin) seems to be the -perfect- ratio for these setups with a stainless line and a big rotor. only downside is slightly shorter lever (which i actually like) and no brake switch.
However,
you can get a banjo bolt brake switch. this takes place of the bolt, has 2 wires, and bam. done.
I used a grom master for a while, and while good, was a bit wooden for my tastes, as was the KTM390 duke one.
Just passing along some info. hope this helps somebody. I have found them for 130 ish, i think the KX ones.
For reference, do you know what size the Grom and Duke masters were?
Years back after a lot of research on blue vs gold dot calipers, I found the difference was that the gold dot has aluminum pistons internally vs steel ones in the blue dot ones.
Frank B did the research when we did our conversions and found out that a Yamaha Zuma Scooter has an 11 MM Master Cylinder. I bought one used on flea bay for $30 shipped if memory serves. It comes with a brake light switch and bolts right on. They work perfectly for this application.
url=https://postimg.cc/WFFRBByw](https://i.postimg.cc/9M1W7VtK/20190331-145247.jpg)[/url]
pretty sure the grom and ktm ones are 12. not sure.
good note on the zuma one timmy, you told me that, i completely forgot that. :patriot: :cheerleader:
:patriot:
I'm running a single silver dot with a Duc 320mm rotor, braided line, and a Yamaha warrior master (four wheeler).
I haven't felt better brakes on another single rotor bike.
I like the Ducati 320mm with bluedot 4 pot R6 caliper and the XS400 14mm master.
Just did a this setup on Paul's STG 2 '76 RD400
Chuck
(https://photos.imageevent.com/supertune/paulsrd400/large/20200503_173507.jpg)
(https://photos.imageevent.com/supertune/paulsrd400/large/20200504_143152.jpg)
I am surprised you can use a 14MM master cylinder with a single caliper. Mine was very wooden feeling with a 14 and marginal at 12. That's why I went on the hunt for an 11MM. That being said if it works that's good.
I'm running a 12mm EX300 master with blue spot caliper and 320mm disc on my TDR.
Feels great and night n' day difference to the stock setup.
i was pretty ok with a 12, like the 11 more, just my .02 preference. fzr rotor though.
FZR rotor for Frank and me too.
Quote from: Kawtriplefreak on July 25, 2020, 11:11:58 AM
I am surprised you can use a 14MM master cylinder with a single caliper. Mine was very wooden feeling with a 14 and marginal at 12. That's why I went on the hunt for an 11MM. That being said if it works that's good.
The stock MC on a US spec RD is over 15mm (5/8) with the single stock caliper. Wooden? A bit. 14mm would be an improvement. Not enough for me to change it though. I would if I ever had to replace it for some reason.
I'm sure the feel would be a lot worse with a blue dot and the MC would have to be changed. Glad all you guys have done the experimenting already.
actually a lot of people prefer a 13 on a stock rd caliper. I tried it didn't like it, prefer a 14. have a 12 on the rear on on the lc, gives really good feel with a much shorter brake lever.
:twocents:
Quote from: Kawtriplefreak on July 25, 2020, 11:11:58 AM
I am surprised you can use a 14MM master cylinder with a single caliper. Mine was very wooden feeling with a 14 and marginal at 12. That's why I went on the hunt for an 11MM. That being said if it works that's good.
FWIW, the Yamaha "...dot" calipers have a bit snakker pistons than the equally available Brembo 4 piston calipers (34/34), so work better with a small MC. Stock RD calipers, as well as Brembo work great with a 13 mm MC
What's the difference between a silver FZR caliper and a blue dot? I'm running a 13mm master from a quad or something, I got it for like $15 used. Asides from needing pads, the setup with the stock fzr (silver) caliper it works very well. I'm also running an off brand aluminum center wave style disc that I bought used on eBay. It looks great and works fine for the street. Loads of stopping power and very light.
i had good luck the silver fzr caliper and 13mm master a swell, id imagine piston area. ?
I've referred to this site for years.
http://www.vintagebrake.com/mastercylinder.htm (http://www.vintagebrake.com/mastercylinder.htm)
(http://www.vintagebrake.com/images/mastercylinder.gif)
well the total piston area is right at 2558.84 for the gold or blue dot calipers. (each caliper) they are 27mm and 30mm, 2 of each in each single caliper.
actual ratio is 26.926 which 27, I believe, is considered ideal. (2558.84/95.03 )
Quote from: m in sc on July 27, 2020, 01:15:03 PM
well the total piston area is right at 2558.84 for the gold or blue dot calipers. (each caliper) they are 27mm and 30mm, 2 of each in each single caliper.
actual ratio is 26.926 which 27, I believe, is considered ideal. (2558.84/95.03 )
27 may theoretically ideal, but there is some preference in there too.
If the "ideal" on the chart is 27, I have found I prefer a little less, maybe 25.
My rider prefers MORE, so he may get 28.
Radial masters are where it's at.
of course. they don't take into account lever geometry either, that makes a huge difference. But, generally speaking as a rule of thumb, thats the target then adjust for feel.
Quote from: m in sc on July 26, 2020, 12:07:55 PM
actually a lot of people prefer a 13 on a stock rd caliper. I tried it didn't like it, prefer a 14. have a 12 on the rear on on the lc, gives really good feel with a much shorter brake lever.
:twocents:
I agree, 13mm would feel too light and squishy for me. I like a little more feedback with the controls.
I noticed the rear brake on my 400 isn't as positive feeling with the rear sets. It feels mushy. Not bad enough to change anything, but I thought it odd as my assumption was that it would feel stiffer with the shorter lever.