var scrollSpeed = 50;
	var step = 2;
	var currentx = 0;
	var imageWidth = 8000;
	var headerWidth = 800;


	var restartPosition = -(imageWidth - headerWidth);

	function scrollBg(){
			currentx -=step;		
		if (currentx < restartPosition){
	currentx =0;
		}

		$('#head').css("background-position",currentx+"px 0");
	}

	var init = setInterval("scrollBg()", scrollSpeed);