How to size a radial master cylinder

[Spondonrider]

I've been looking at options for replacement master cylinders on my Executive and have generated a question in my mind...

It seems, from some of what I read that its not just a matter of cylinder size. I understand the whole lever ratio thing but on a couple of web sites the 16x18 radial was listed as a perfect replacement for bikes running 14mm non radial master cylinders. Is there something about the lever ratio that makes the 16mm a 14mm replacement or is it just that it will work so is good enough? Has anyone installed radial master cylinders on their Laverda using the stock calipers? Would it work?

 

[Vince]

I have 4 spot Bembros on my 3c with a stock master,dont know if its a 15 or a 14,280mm disc's,braided lines and that worked well for a while but the last couple of rides it didn't have the bite of earlier,the topend is off at the moment but its
coming back with all of the about but a Brembro 16x18 Radial Master I had laying around,I think Cam,our tame engineer did a spread sheet a while ago on this topic but referring to what would happen to clutch hand pressure with different sized Radial masters,there must be a correlation between the std and Radials,pretty sure there is a leverage advantage with the Radials,good info re this should be a sticky at the top of the Tech section.

 

[mkavci9]

hello, i have a problem and i hope that you will help me. I'll borrow this topic.

I wanted to clean my Clutch master cylinder, and i didnt know that petrol(gasoline) destroy the seals shame

I have to repair my Clutch master cylinder and I dont know wich kit is corresponding to me. I have Laverda ts1200 y.1982  ttp://riviere67.free.fr/Routieres/LAVERDA/lav-1200-tts.jpg

On the Brembo Clutch cylinder are this two numbers  JO 15  and  10.2729 01. 

I find this piston kit on ebay  http://cgi.ebay.com/DUCATI-LAVERDA-MOTO-GUZZI-M-CYLINDER-REPAIR-KIT-15MM_W0QQitemZ260457879565QQihZ016QQcategoryZ10448QQcmdZViewItemQQ_trksidZp3286.m7QQ_trkparmsZalgo%3DLVI%26itu%3DUCI%26otn%3D1%26ps%3D5

I measured the dimensions of my piston and in the middle is 15.85 wide, that means that cylinder liner is probably 16 mm. What you say Is uperr kit coresponding to me or I have to search one 16 mm kit?

Is somewhere possible to find only the seals?

thank you very much
Martin

 

[lavgert]

Hi Martin,

if your piston is 15,85 in diameter - your clutch master cylinder is a PS15! The repair set is the same for frontbrake, clutch and rear brake. As far as I know, you can't get the seals only. But you can get it cheaper here:

http://cgi.ebay.at/BREMBO-Reparatursatz-Handzylinder-PS15-auch-Fuss_W0QQitemZ390048726459QQcmdZViewItemQQptZMotorrad_Kraftradteile?hash=item5ad0b73dbb&_trksid=p3286.c0.m14

Ciao, Gert

 

[mkavci9]

thank you for help, but my piston is not like that on your link. It looks like this
http://www.kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=1591 

OK, now I know what to search.

greeting, Martin

 

[jotacorsa]

ed, it has been a while but there was an article in LVV detailing master cylinder sizing with different caliper and rotor combinations.

doing some rummaging through files i found a photo copy. it isn't a great copy and might not scan well but perhaps someone has it in their library. i was in two segments the first being in LVV 147. i don't know when part 2 was printed.

it mentions martin johnson and nick holt both running 19mm radial masters with 4 pot brembos. so a 16 radial might be the ticket for use with F08's.

are you thinking of  a  radial conversion for the clutch, too?

cheers,
scott

 

[Spondonrider]

No, no radial conversion at all. The question came up because I wanted to switch to remote master cylinders, to gain clearance to the Executives fairing so I could mount higher clipons...which makes my bad back and neck happy. So you see, it all started one fine summer day back in 1981 when I crashed a Suzuki and (literally) broke my fool neck! In the end I found a couple of new Nissin master cylinders, non radial with remote reservoirs that were cheaper than used Brembos on Ebay with busted levers. This all started back when you and Diane were gallivanting around Europe so you missed the original discussion.

Now your all caught up!