Kiril Varbanov wrote:....Otherwise, I agree with what riff_raff says. The tiny carbon fiber disks can take about 900 degrees, but they are easily overheated in slip conditions due to the great friction.
While it is true that 13K revs are a ballpark number, I think you can afford a bit more if you have had a fresh one.....
In simple terms, the heat load absorbed by a slipping clutch is the equivalent amount of power lost from friction. The power converted into heat in the clutch disks can be roughly calculated from the relative rpm differential between the sliding clutch disks times the amount of torque being applied at the clutch input where slippage occurs, divided by the appropriate shaft HP constant. Convert that HP into thermal energy, and then calculate the temperature rise that thermal energy input produces in the carbon clutch disk mass. If the heat input to the 1.0kg mass of carbon clutch disks from slippage produces a temperature rise in the carbon disks beyond what they can safely handle structurally, then there is likely a problem.
In reality, with regards to thermal overload of a carbon clutch, things are a bit more complex. Due to relatively poor heat transfer properties thru the thickness of carbon clutch materials, the temperature right at the disk surface where the slippage occurs can be significantly higher than the rest of the clutch disk body. Carbon clutch disk materials can begin to rapidly degrade from oxidation at temperatures in excess of 1800degF.