a j swingarm should be 2kgs lighter than a P model swing arm. A J model swingarm was handmade in 1991-1992. the L model is also lighter than the Pmodel about, 0,8kg. so go for the J model.

difference between J and L = 1,2 kg

 

j model swingarm: 5,7kg with bearings

L model swingarm: 6,9 kg with bearings

 

 

 

98-02 zx6r rotors: (296mm) 5,7 lbs 2,58

alu rear sprocket: 47t 520: 0.85lbs 0,39kg

braking rear disc: 1,3 lbs 0,59kg

 

zx7r p model rear 6 inch wheel: 23,5lbs (incl stock sprocket and rotor) 10,6kg

 

zx7r swingarm -- 8.785 kg
zx9r swingarm -- 6.755 kg (brace model)

j model swingarm: 5,7kg (no sleeve)

j model with sleeve: 6,7 kg???

9F swingarm 5,9kg (no sleeve)

 

 

zx7r front: 4,9

zx9r front 2001+ 4,53kg