for models
R50/5 R60/5 R75/5
R60/6 R75/6 R90/6 R90S
R45 R65
R60/7 R75/7 R80/7 R80 R100/7
R100CS R100RS R100RT R100S
till 09/1980
S/S hex nut M10x1.5 SW 14 between cylinder and cylinderheads on the outside bolts.
made of SS for comparison 23111230599
fits all R2V Boxer
M12 with wrench size 17