Hi, I'm just about to purchase a pedal box for my Yamaha fzr 1000 powered Fiat 126. Included with the new set up I have the choice of 0.625", 0.7" and 0.75" master cylinders but I'm unsure what this means and what I will require. What size will be suitable for the Yamaha clutch and what pair will I need for my brake setup (240mm punto turbo disc conversion). The pedal box has a 5:1 ratio and bias bar if this has any bearing on MC selection.

If anyone could give me a quick schooling I'd appreciate it. Thank you!

Are you running Punto Turbo front discs and callipers on the front and Punto Turbo rear discs and callipers on the rear ?

In which case you have 54mm bore callipers on the front and 34mm bore callipers on the rear -- which is fine for a nose heavy FWD hatchback but not ideal for your weight distribution.

Try a 0.7" bore master cylinder on the front and a 0.625" on the rear as the intial choice. If can't get the front rear balance right with the bias bar set somewhere near its' central position with that set up try a 0.75" which are very cheap from Land-Rover specialists.

Ok well that is definitely food for thought. Thanks. So what about the clutch? What is it that dictates MC selection? Thanks again.

[Edited on 25/6/13 by Fiat126fzr]

I've worked out that for the clutch i need a 5/8 (0.625"MC...