Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > Brake master cylinder sizes - Jap stuff

[Cranker V2]

Just a little bit of info for the single minded ones..........


http://www.rg500delta.com/RG500_chas...re%20sizes.pdf

[Ghost]

Good find Mike. I'll look out for a 1/2" jobbie now.

[bradders]

This has to be one of the most useful posts I've seen on here for years.

[skidlids]

1/2" M/cyls were used on Steel framed CBR600s that had two calipers each having two pistons and of the sliding type, I always felt they worked well, Early Fireblades also used a 1/2" M/Cyl (there chart is wrong wrt to this one), in this case it was of the remote reservoir type and was connected to two calipers each with 4 pistons. The brakes on these early Blades I always found a beed weedy and upgraded mine to 5/8" (15mm ish) which did improve things.

When racing the TL1000SV which again came with two 4 piston calipers and a 5/8" Master, I upgraded to the GSXR 6-pot calipers and ended up going to a 3/4" (18mm ish) Nissin Master-cylinder before changing to a 20 X 19 Brembo Radial.
These days on both my 998s I have the AP adjustable ratio CP4125 M/Cyls as these allow you to dial in the feel that you want by adjusting the pivot point. Not saying I like my AP brakes but I'be been up to Leeds today and come back with a set of CP4466 6-pot calipers, CP4125 M/Cyl and some 320mm diameter 6mm thick race discs.
Quite a few modern bikes are now running 3/4" Nissin Radial M/Cyls with twin 4-pot calipers.

One thing that often gets missed is the position of the pivot point, the Brembo RCS has a couple of positions for it, the Magura has 3 I think and the AP has quite a range

I probably have 10 or more of my old jap bike M/cyls stored away, including several newer radial ones, I'll have to dig them out and see what I have.

[bradders]

Originally Posted by skidlids

I probably have 10 or more of my old jap bike M/cyls stored away, including several newer radial ones, I'll have to dig them out and see what I have.

bring some with you to Brands kev in case the Magura 16mm is way too much for one disc!!

[badgerpilot]

Not got a spare rear master cylinder for Badger have you Skids?
Mines shot and Nelly thinks you'll probably have a spare one lying around.
(see for sale/wanted section)

[bradders]

anyone know what size the Multi front brake is?

[bradders]

another numpty (not Multi) question:
which is bigger 14mm or 5/8? Instincts tell me 5/8 is biggest looking at the bikes that are listed (and 1/2 being 13mm from dodgy memory)

[skidlids]

5/8" = 15mm ish
1/2" = 12.5mm ish

So sizes as they go up are

1/2"
13mm
14mm
5/8"
16mm
18mm
3/4"

I'll see if I can dig some out tomorrow, but the main priority tomorrow is to cure the carb leak on my Class B monster, probably only a sticking float.
Also tomorrow I have to decide if I should connect up its second caliper or remove it along with the second disc

[Ghost]

Some slight annomolies with Kevs sizing.

1/2" =12.7mm approx 13mm

9/16" =14.28mm approx 14mm

5/8" =15.875mm approx 16mm

11/16" = 17.46mm Nearer 17 than 18

3/4" = 19mm or as near as makes no difference.

Soory Kev just reread your post and it wasn't conversion but the size hierarchy