actually before you 'tap' on the stem bolt with the handle of the hammer make sure it is still engaged in the threads of the 'wedge' so that does not drop down the steerer tube.
However more importantly here is the fact there is a "MAX HEIGHT" limit marked on your stem. besure you do not raise the stem above this mark. you might be there already. raising the stem above this limit could result in injury or damage to the bike
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk