The Falco has a hydraulic-actuated clutch, as opposed to the cable-actuated clutches found on many sportbikes. There are advantages and disadvantages. Some would say the cable clutches have better feel, or one-to-one connection between ones hand and the clutch action. But the hydraulic clutch, while somewhat vague at times, suffers none of the cable friction. This, coupled with the vacuum feedback circuit, means less clutch effort for a heavy-springed big-bike clutch. Also, in theory, a hydraulic clutch should be very reliable with no routing difficulties, lubrication issues, or cable breakage. I've found this to not be the case, as bleeding and the seal failure of the Brembo cylinder are more of a problem than they should be.
The Falco clutch fluid has always turned black a couple of weeks after changing it. This has not been a problem, as I flush it every oil change. But recently on a trip, I lost a large portion of my clutch travel. The seal seamed intermittent, and the last little bit of lever travel that did work was very hard to actuate. Needless to say, my hand was cramped up in no time and I did not look forward to shifting. No fluid had been lost, but I suspected the slave cylinder ("control cylinder") based on the experience of many a Falco and Mille owner. I removed the cylinder for inspection.
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The clutch slave cylinder lies behind the countershaft sprocket cover. Three bolts hold it in place. There is a weep hole in the housing ("flange") behind the cylinder, and on my bike there was a few drops of hydraulic fluid around this hole. If you are replacing the cylinder, you should probably remove the clutch hydraulic line first, but for inspection it is not necessary. |
| You can remove the piston from the cylinder by pumping the clutch lever a few times. Unlike a brake cylinder, there is no square seal in the bore. Instead, the piston is more like an accelerator pump or fork seal, with a one-way wiper on the piston itself. The bore should not be scratched, and the seal should be flexible and intact. Any nicks or cracks, and a rebuild is in order. The rubber seal on the flat end of the piston is simply a grease seal for the end of the actuator rod. It should be cleaned but is not critical. On my bike there was some grooving of the actuator rod where it touched the seal. If this grooving is sharp, you would want to lightly sand it. |  |
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The slave cylinder bolts to a spacer, or flange. This is easily removed and should be cleaned to keep sand and chain grit away from the cylinder. Clean the actuator rod, particularly where it touches the seals. |
After cleaning the piston and bore with brake cleaner, I lubricated the seal and bore with fresh brake fluid and reassembled them. A dab of fresh grease in the hole at the end of the piston will reduce friction on the actuator rod. The torque spec on the three bolts is 8.7 ft-lb (12 Nm). The torque spec on the bleeder nipple is 10.8 ft-lb (15 Nm). After refilling and bleeding the system, my clutch lever was restored to its original feel.
Had a rebuild been necessary, there are a few options. I've been told Brembo does not sell a service kit, but I believe some manufacturer in the UK does (please email me if you have purchased one). Outside of buying another stock cylinder, Evoluzione Cyclesports sells a replacement. This replacement has reduced clutch effort, but at the price of a different feel that you may or may not like (generally, more leverage means more travel is required). I would speak to them before ordering to make sure the countershaft cover can fit over it, as the original Mille cylinder they offered required some cutting.
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