set value selectpicker code example
Example: selectpicker set value jquery
The value is correctly selected, but you didn't see it because the plugin hide the real select and show a button with an unordered list, so, if you want that the user see the selected value on the select you can do something like this:
var text = $("select[name=selValue] option[value='1']").text();
$('.bootstrap-select .filter-option').text(text);
$('select[name=selValue]').val(1);
Edit:
Like @blushrt points out, a better solution is:
$('select[name=selValue]').val(1);
$('.selectpicker').selectpicker('refresh')
Edit 2:
To select multiple values, pass the values as an array.