Hector slam lidar /clock topic not publishing

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Hi I am trying to make use of hector slam i run the rviz and nothing comes up i run the .bag file on the hector wiki and all works ok but its not taking in the data from my lidar. looking at the ros topics ive no /clock publishing looking at other solutions suggests having <param name="use_sim_time" value="true"/> in the launchfile which i have allready. when i run the bag file

rosbag play Team_Hector_MappingBox_RoboCup_2011_Rescue_Arena.bag --clock

it plays all the data not just the clock. has anyone any idea where i may be going wrong? all help appricated

how can i publish real time clock topics?