Sorry, can't help you with the length but i would assume they would be similar but different lengths to suit different swingarms, shouldn't be that hard to make one 'right'
Part # = 43007-1101
Part Description = TORQUE ROD
Model Count = 2
KX250-C2 84 250 KX250 MOTOCROSS
KX500-A2 84 500 KX500 MOTOCROSS
Part # = 43007-1014
Part Description = REAR BRAKE TORQUE LINK
Model Count = 4
KX250-A6 80 250 KX250 MOTOCROSS
KX250-A7 81 250 KX250 MOTOCROSS
KX420-A1 80 420 KX420 MOTOCROSS
KX420-A2 81 420 KX420 MOTOCROSS