You believe incorrectly mate.brys wrote:I have 2002 firestorm calipers on (I believe they are the same as yours). I'm using the standard 14mm vfr M/C and it's awesome, tried fitting a 17mm one from an SP2 and just didn't get the same compression and feeling at the lever. Odd as I've always believed that your should change the M/C to suit..
Firestorm:

600RR:

Most importantly the pistons in Firestorm calipers are 27+30, those in the RR calipers are 30+34 (I think, may even be bigger).
So there you have it

Modern calipers almost all have pistons ITRO 30+34, so almost all radial master cylinders will work your calipers very nicely. Just cost a bit more than an equivalent 5/8" regular one.