CSK165 H/Duty Clutch Springs for Kawasaki ZX6R P7F/P8F/RF9/RAF/RBF/RCF/RDF/REF/RFF/RGF (599cc) 2007-2016. EBC clutch spring kits are 10-15% stiffer than standard and are sold in engine sets. Genuine EBC Clutch Spring Kit, to suit the following applications.