Have been out there several times previously on 800 and 1000cc twins. Wouldn't take anything heavier and you need to be confident that you can handle these machines in dodgy sand.
Their are a few escape routes on the big beach east of Israelite bay but some could be difficult to find- gps, google images would help. The best thing is to get the tidal info. Several 4wd vehicles have been lost on these beaches because sand washes over the seaweed hiding the hazard below.
not neccessary to ride these dunes