ZX12R (2005 )

Hi, My above 12 with 179000kms has developed an oil leak out of the Balancer. The workshop manual say's to
split the cases, which also means removing the engine, quite a daunting task to replace a $5 Au "O" ring.
Is there an easier way to remedy this problem. I've removed the balancer bracket/holder and i cant see any way of replacing the "O" ring without removing the balancer shaft. Is it possible to pull the shaft out a few millimetres without things falling off the shaft in the crankcase to replace the seal or is it a lost cause. I hope someone can steer me in the right direction. Have a good on, Merv.