You do not have sufficient permissions to access this page while making a plugin

Solution:

Two alternatives. You can add an invisible sub menu page, or work with the URL: /wp-admin/options-general.php?page=crud&create=true.

For this second option, it’s just:

function crudboard()
{
    $add_new_url = admin_url('options-general.php?page=crud&create=true');
    ?>
    <div class="wrap">
        <?php if( !isset( $_GET['create'] ) ) { ?>
        <h2>
            Motors
            <a class="add_new-h2" href="<?php echo $add_new_url; ?>">Add New</a>

        </h2>
        <table class="wp-list-table widefat fixed pages">
            <tr><td>Start page</td></tr>
        </table>
        <?php } else { 
            include 'create.php';
        } 
}

And a sample create.php file:

<?php
/**
 * Create page
 */
?>
<h2>Add new Motor</h2>
<table class="wp-list-table widefat fixed pages">
    <tr><td>Create page</td></tr>
</table>