Join Date: May 2017
Location: Ailsa Craig, ON, Canada
Options for 999 Clutch Master Cylinder Replacement
I've spent several days researching this topic, both on this forum and elsewhere, and feel compelled to start a new thread to consolidate the information.
Background: I just picked up a 2003 999 with 14,900kms on it. On my first ride, I was caught by surprise when the bike randomly stalled while downshifting to first at a stoplight. The bike has had the valves adjusted, timing belt replaced, was dyno tuned to richen up the idle mixture and seems to idle very well in neutral. After a few more days and a few more stalls, I found I was unable to downshift below fourth gear. That's when the lightbulb went off and I realized that my clutch was likely not fully disengaging. Sure enough, bleeding the master cylinder in the reservoir and then bleeding the slave cylinder had it working perfectly again...for about the next 60kms. I don't see any external fluid leaks, but the system is definitely ingesting air somehow.
About the bike: Factory master cylinder with aftermarket aluminum reservoir cover, adjustable Pazzo clutch lever (which I have set for maximum stroke right now), new Oberon 29mm slave cylinder, new clutch hose, new crush washers, new Barnett clutch assembly and new throwout bearing. When I say new, I mean one year old with less than 800km of riding. I have flushed and bled the system using Motul RBF600.
The fact that everything works beautifully immediately following a bleed has me convinced that the clutch itself isn't a problem. Does it seem logical that replacing the master cylinder is my next step?
My question for the community here is: what is the generally preferred resolution to master cylinder issues? The options I have come up with are:
1. Order a new OEM 999 master cylinder that will fit up with no problems. I've read some anecdotes on this forum that service parts are of better quality than the original on my 2003 bike. Is this true? This sounds like the easiest approach and I still get to keep the clutch safety switch.
2. Retrofit a Brembo RCS 16 master cylinder. I've read several accounts of riders having issues with the cylinder limiting steering angles and the lever interfering with the LH switch assembly. There's also the hassle of sourcing and mounting a remote reservoir. Finally, I know that this will increase clutch effort to an extent. Is it worth all the hassle? Will this prevent me from having to bleed my clutch before every ride for good? It seems that I will lose the clutch safety switch with the aftermarket solution. I also can't use my Pazzo lever...I could see this leading to replacing the brake master cylinder with an aftermarket assembly as well.
3. Retrofit a master cylinder and reservoir from a newer superbike (e.g. an 1198 or 1199). I've found one account of this working out well, with the complaint of mismatched lever aesthetics. Will my Pazzo lever fit a newer model's master cylinder?
For those of you who have been here, what was your experience and what do you recommend? Is it possible to have a worry-free/trouble-free clutch on a 999? I've never had to sweat wondering whether or not my clutch is up for a ride. I live out in a rural area, but my ride into work does lead me through a city and I need more reasonable stoplight manners.
Thanks for sharing your wisdom! Cheers.