GP 250/SSP 400    
SSP = SuperSport until 500ccm 2Strokes -- until 400ccm 4Strokes 4Valves -- until 900ccm 4Strokes 2Valves -- Single cylinder  
  until 636ccm 4Strockes 4cylinders -- until 750ccm 4Strockes  2cylinders   
R6, CBR 600, ZX 6, GSX R 600, Ducati 748, 749
SBK = SuperBike over 636ccm 4Strokes 4cylinders -- over 750ccm 4Strokes  2cylinders  
Ducati 916-999, Aprilia Mille, TL 1000, VTR-SP1, GSX R 750, ZXR 750   +  R1, CBR 900, ZX 9, GSX R 1000, Ducati 1098
 This Season we combined the former SBK (750cc) with the STK (1000cc)
 ..we then renamed  SBK  the class over 600