Hayabusa M/C with GS calipers

[Guest]

I have a slightly tweaked '89 GSXR750 front end in my garage with Hayabusa brakes. Eventually it will be put on my bike but I'm holding off for now. My stock clutch/brake perches and levers are really worn and loose, and I already test fit the clutch side with a GS cable and it works.

Is it safe to use the Busa master cylinder with a single disc GS front brake? I'm sure the piston size is different in the newer m/c, but if possible I'd like to use them on my bike to save some money. Plus there are soo many aftermarket adjustable levers available.

I did try searching btw.

[Agemax]

i cant see why it shouldn't work ok, i run a B12 M/C with a single disc and it has massive stopping power, better than stock GS twin disc set up

[salty_monk]

The piston size & ratio will be completely different. Try it but be careful. My suspicion is that particular MC will be set to move a lot more fluid more quickly so you might end up with very "on/off" sensitive brakes....

[Toasty]

That's definitely something I'll have to test. I did a little research, apparently it can go on a single disc GS500 without issue. I'm not sure what the MC bore is on the 550 but the 500 is 1/2" and the Hayabusa is 5/8"s.

link


Edit:
Although, according to this http://www.vintagebrake.com/mastercylinder.htm . The ratio (38mm single disc, 5/8th's MC) is 5.73:1... supposedly the ideal for single piston calipers are 14:1 - 12:1. Stock is only 7.37:1 though .

Bleh... I dunno.

[salty_monk]

The stock Single Suzuki on the GS uses a 14mm piston dia.

I don't know why it's metric on the single but 5/8" on the doubles...! (Double is also 5/8"). Using the 14mm on the double gives a spongey lever. This would definitely have some kind of effect in the direction I described above as the piston is bigger (approx 25% more piston face area).