It's in the mod/thewire/views/default/thewire/forms/add.php and reply.php.

Urm...it might not be--that's for the wire messages.  What exactly are you trying to change the limit of?

The amount of characters some one can write on the river

might this help ?

<form action="http://localhost/BrainRetain/action/thewire/add" method="post" name="noteForm">
<textarea
    name='note' value=''
    onKeyDown="textCounter(document.noteForm.note,document.noteForm.remLen1,140)"
    onKeyUp="textCounter(document.noteForm.note,document.noteForm.remLen1,140)"
    id="thewire_large-textarea"
    >
</textarea>
<div class='thewire_characters_remaining'>
<input
    readonly
    type="text"
    name="remLen1"
    size="3"
    maxlength="3"
    value="140"
    class="thewire_characters_remaining_field"
    >
    characters left
</div>           
<input type="hidden" name="method" value="site" />
<input type="submit" value="Save" />
</form>

@Dhrup thanks Ill try that out

@imcobarn -  Make sure keep a record of your changes in case you upgrade because you know any changes to core code will be gone unless you use a plugin to achieve this. Just a thought

How is this done in 1.7.1? \riverdashboard\views\default\riverdashboard\post.php doesn't exit there anymore. Modifying /mod/thewire/views/default/thewire/activity_view.php allows posts of longer length to be entered, but it's not sufficient to display them on the wire.