[gmdboston]

All stock shocks on Kawasaki's (at least the late model stuff) are nitrogen charged shocks. There is oil in the body and res. The nitrogen in the ZX shocks is in the res. separated by either a piston or a rubber bladder. His shaft seal has been cut and the N2 pressure in the bladder has pushed out the oil. Tell him not to ride the bike until it's fixed, and not to think it's fine because it stopped leaking. Once the bladder has fully expanded, it will stop pushing oil out when the bike sits. However, when he rides it, the pumping of thte shock will push out the remaining oil and make the bike dangerous, as well as wear out the shock body. Right now he has a $125-$150 repair. If he keeps riding he will need a whole new shock.