Twin Disc Master Cylinder

The 3 1/2 forum
FenlandExile
Posts: 1
Joined: 24 Feb 2022 20:19
Location: Northumberland UK

Re: Twin Disc Master Cylinder

Post by FenlandExile »

Re this topic, can I ask if a 350 Sport really needs twin discs? I know not all bikes have this option.

The reason I ask is I am just recommissioning my 78 350S, that has stood for about 10 years, that has the twin discs fitted. One caliper and disc is in a pretty bad way, and if the single disc set up gives decent performance then I could convert it to this.

If I want to stick with twin discs then I'm going to need some new caliper pistons. Are these available anywhere? (Seeing another post on here talking about making them out of Stainless steel I'm guesssing not....)
I did notice on eBay some 41mm diameter pistons for Grimeca GM1 cart calipers. They are too long at 18mm rather than 15.5mm, but I could modify them easy enough. . . . no not with a hacksaw. :roll: Anyone already tried/done this?

Cheers.
George 350
Posts: 450
Joined: 16 Jun 2007 09:43
Location: Northampton

Re: Twin Disc Master Cylinder

Post by George 350 »

Hi,
I too have a '78 Sport. To me a single disc is fine unless you aren't a lightweight or really ride hard. Only time I really felt I needed a better front brake was when in the alps loaded with camping gear. I do have a larger disc/different caliper on mine - Kawasaki - but only went that route as good discs/calipers were unavailable or cost silly money in the mid '90's.
Standard disc weighs a ton too, so a big unsprung weight saving to be had.
George
George
350 sport 1978, 350 Strada 1978
650 Norton 1967, 650 Kawasaki 1977 and 650 Enfield 2019
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Twin Disc Master Cylinder

Post by Steve Brown »

The standard single disc works fine as a stopper but lacks any feel-wooden even. It's easy to cure with a smaller bore master cylinder and a good number of us have used a cheap generic item. Available online for many smaller bikes and very cheap with the added advantage of a stop light switch.
As George points out, a twin disc set up adds a lot of weight to the front wheel and costs more than a replacement M/cyl.
At the last Cadwell trackday I managed to boil the front brake fluid on my single disc Sport and thought I must be braking too much/too hard. I then realised I hadn't changed the fluid for a number of years :oops: that was the real culprit.
All donations to the rest home for old Camels, Leicestershire.
Mark
Posts: 145
Joined: 28 Jul 2012 15:57
Location: Cannes, France.
Location: Cannes, France.

Re: Twin Disc Master Cylinder

Post by Mark »

Just bought the splitter on eBay.
Thanks for the heads up Dunk.
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