Clutch piston cylinder and spring rate changes...

[buell-fan]

Does anyone know if the new easy pull clutch cylinder piston was redesigned because it was needed because of the easy pull clutch kit's longer spring lengths, or was the new reduced effort piston designed for better lever pull only?

The reason I need to know this is when I got my bike the dealership had already installed a reduced effort clutch kit. It seems as though the clutch pull is really too easy (two fingers) and the spring clamping rate is a bit weak for my liking when putting full throttle to the bike while racing in high rpms. Because I have the original heavy clutch springs and piston I am going to change them out, but was only going to put in the heavier springs for the stronger clamping pressure and not the piston cylinder if it is not required; so lever pulling effort may be eased by the new piston but with the benefit of heavier spring clamping pressure on the clutch disks.

[Mike]

From what the EBR guys told me (or from the proverbial "horse's mouth") -
Both the piston had changed (don't know "what" had changed), and the actual clutch pressure plate spring was changed. They told me that if I ride any canyons, do much on the dyno, or "push it much", that it's not a good idea to do this swap, because of the lighter pressure plate spring. Much less overall clamping force.

I dropped the idea. The lever force isn't all that bad in stock form. At least to me.
If I were you, I'd have them put the "original" pressure plate spring...back in place.

Mike

[buell-fan]

Well I put the original springs in for the heavy clamping pressure. I didn't change the new easy pull clutch actuator piston assembly though. The change added a only a few pounds to the lever pull, and I get back all of the original clamping force needed for heavy loads at high rpm's.

[Doosh]

One possible solution to the heavy stock clutch pull is the Suter slipper clutch. I use the Stuter clutch with twin staked 1000N springs with no issue although it's very sensitive to clutch pack size. You are essentially trading performance for significantly shortened service window, especially at soft slip set-ups.

I've run both the original Suter design with the single 2200N main spring and the new design with the stakes twin springs. The newer design has a better feel at the lever.

I'm also using the Oberon clutch slave on that bike, though I don't believe that to be the issue. But, it's something on that set up that's different than the stock 1190.

[roadking1]

I had the dealer just put in the new actuator assembly and leave the stock springs in place. Given the massive torque of the bike, putting in lighter springs made no sense to me. While still heavy, the clutch is noticeably lighter than before. And I have confidence that I will not be prematurely burning the clutch plates do to a reduction in clamping force from the new springs.

[buell-fan]

I had the dealer just put in the new actuator assembly and leave the stock springs in place. Given the massive torque of the bike, putting in lighter springs made no sense to me. While still heavy, the clutch is noticeably lighter than before. And I have confidence that I will not be prematurely burning the clutch plates do to a reduction in clamping force from the new springs.

Good move. I bought mine already changed out by the dealer, but got the originals as part of the sale. Yesterday while doing the spring swap I was pretty surprised at the little amount of clutch friction area of these plates actually have versus power of the bike as compared to my Shovelhead Harley clutch disks. My old bike has three times as much friction material and steels! While I understand these clutches were designed predominantly for road course track use and weight savings, a re-designed unit with just ten percent more friction disk material will be better for the everyday sport rider and probably the racer alike.

[dblast]

If this helps anyone, I checked my stock clutch pull with a quality spring scale. It took 28 lbs to pull clutch all the way to the grip and 18 lbs to maintain. I installed an Oberon CLU-1125 slave cylinder. It now takes 17 lbs to pull it to the grip and 10 lbs to maintain. I used DOT 5 fluid in all my clutch systems.