Header BG position not full width of internal pages

Hi
I use University template
Header BG position on Home page is full width of browser
Same image on Header BG position on all internal pages is scaled down to the width set in template settings.
Why does this happen
Can Header BG be made to go full browser width where ever it is used.
Without full width it is identical to Header Bottom

Hi,
Could you please provide me with a URL to your website, either here or via PM (click the “Private Message” text underneath my avatar) so that I may analyze it? On the demo, the background is fullwidth also on pages other than Home page.

Hi

Thanks for helping

It is for myRainCheck.com

I use this override code which may affect it... but I use the template on another site which also does not go to full width in header_bg

/*
#------------------------------------------------------------------------
# University - May Joomla! template (for Joomla 2.5)
#
# Copyright (C) 2007-2014 Gavick.com. All Rights Reserved.
# License: Copyrighted Commercial Software
# Website: http://www.gavick.com
# Support: [email protected]
*/

/* Here you can include your override CSS styles */
#gkHeaderNav {
position: fixed;
background: none repeat scroll 0 0 rgba(50, 48, 47, 1.0);
padding-bottom: 0px;
padding-top: 0px;
}
}
#gkHeader_bg .gkPage { max-width: 1920px; width: 100%;}
#gkHeader_bg { padding: 0; }
.customSuffix .gkPage {
max-width: 100%;
}

.single-page > .header {
background-size: cover;
}
#gkHeader {
background-size: 100% auto !important;
}
.frontpage #gkHeader {
background-size: auto 100% !important;
}

I need to see your website to check the issue.

I did say that it was www.MrRainCheck.com

Sorry, I've missed that.
Did you edit also template php files? I can see custom css classes in your code, in this case I'm not able to help.