| Steve,
All the aftermarket slave cylinders do to achieve a lighter clutch lever is to increase the bore in the slave piston. Now, depending on the bore and stroke of your master cylinder (I think the 916 is 16 mm ???) it can only pump a given volume of hydraulic fluid. By definition, if the bore of the slave cylinder increases, then given the total amount of fluid that the master cylinder can pump into it the stroke that the piston can move is obviously less than the original slave.
Some of these slaves (at least STM ones) come in two bore sizes - 28 mm and 30 mm. I bought a 30 mm one for my ST and found that despite bleeding it until I was blue in the face, the standard master cylinder simply could not pump enough fluid into the 30 mm bore to move the slave cylinder far enough to completely disengage the clutch. I sold it to KeefyB who put it on his 999S without hassle because the 999S master pumps more fluid. I might have been fine with a 28 mm unit, but in the end I went for a standard uprated version (the one with the big torx looking thing).
You might also need a different clutch actuator rod as well. They changed to a longer rod in 2001 so if your bike is earlier than that it will either need a spacer to fit the slave (STM's come with one) or a longer rod. You need to be sure of your model years as well, although my bike was registered in 2001 it was made in late 2000 and had the shorter rod. |