Fitting a GSX-R/R1 radial master cylinder to an FZ1

[FazerMonkey]

Just come back to PB after numerous years shackled to Bike mag (renamed Classic Bike)..........rejoice. Anyway, I've got an 07 FZ1 and was going to fit an R1 radial master cylinder as I've heard they make a big difference. Fitted Goodridges and Ferodo Sintered pads so far but the brakes are still a warm shade of shit. But, there's no R1 radial m/c's around although I have found numerous GSX-R radial m/c's. My first Q is whether anyone knows if a GSX-R radial m/c would be a straight bolt-on? and whether it would make a difference? I know the internal bore of the stock FZ1 front brake cylinder is 16mm........after that, I'm Forrest Gump. Any help much appreciated..... thumbsup.gif

[David W]

You can get a Brembo for good money if you shop around. There's no substitue for the real thing, as they say.

[FazerMonkey]

I'm hearin yah but I've got no idea which one to fit, there's so many variations, 16x16, 18x16, 19x16 etc that it's a lot of cash to get it wrong and I don't understand enough about it to make an informed choice - it's all a bit of a dark art with differing opinions on which would give best results. I do know that the R1 radial m/c goes on and works a treat as it's matched to the system but they're hens teeth, none anywhere, but loads of GSX-R ones available at the right money.

[lorenzo]

If you want slightly firmer stopping, but with a bit less movement, then a slightly bigger bore would be the way to go, perhaps an 18. I got myself one off a late model blade a little while back, it was cheap as chips too and feels great.

Regards the brembo one, the first number is the bore, like I said 18 is a good start for most people, and the second number is the ratio at the lever. Gawd only knows what that's about, but an 18x19 is quite popular. Whatever you do, be careful if you're buying on ebay 99% of them on there (the cheap ones) are copies and will leave you in a ditch if you're not careful.

[FazerMonkey]

Ahhh, thanks for that. So a slightly bigger bore is the way to go, wonder what bore a GSX-R radial is. What bike did you fit the Blade one to? What was the improvement....power, feel, bite? I'm looking for a bit more initial bite with more stopping power from the same lever input as now.

[David W]

The new Brembos are adjustable between 20x19 or 18x19. The first number is the distance (mm) between the lever pivot and the centre of the piston. The second number is the bore size (mm). Both will work on a two caliper bike. My SP2 has an 18x19, and I also used an 18x19mm on a ZRX1100 to good effect. Some people recommend the 20x19 for a roadbike which gives slightly less lever travel.

The other sizes are for single caliper bikes and clutch m/cyl.

[morepower]

Bigger bore give less travel and a firmer lever. With the firmer lever it takes more effort to pull the lever. If you go too big the brakes become wooden and stopping power is more about how hard you can pull the lever and not about the mechanical advantage the ratio will give you. The smaller bore or lower ratio will give you more power with more lever travel. So if your lever is too soft and needs to be firmed up use a bigger bore or higher ratio. If the lever is too firm then use a smaller bore or lower ratio.