for a easy calculation off your engine CC
Bore = 66mm
Storke = 57mm
pi = 3,1416
3,1416 x 6,6 x 6,6 x 5,7 / 4 = 195,00 cc´s
BORE SIZE MM_____OVER_______CC'S_____________+3 CRANK
66.00 - STOCK - 195CC - 205CC
66.25 - .010 - 196CC - 207CC
66.50 - .020- 198CC- 208CC
66.75 - .030 - 199CC - 210CC
67.00 - .040- 201CC - 212CC
67.25 .050 - 202CC - 213CC
67.50 - .060 - 204CC- 215CC
67.75 - .070 - 205CC - 216CC
68.00 - .080- 207CC - 218CC
68.25 - .090- 209CC - 220CC
72.00 - STOCK BB- 232CC - 244CC
72.25 - .010- 234CC- 246CC
72.50 - .020 - 235CC - 248CC