Empty space appearing at the end of my carousel

I have used this script to create an infinite carousel on my website here. It's been customized with CSS so the first and last items are displayed half way.

If you keep clicking the right arrow, you will end up hitting an empty space at the end. So far I haven't been able to fix this. Can anybody offer any solutions?

Here is the relevant script:

/**
 * @author Stéphane Roucheray 
 * @extends jquery
 */
jQuery.fn.simplecarousel = function(previous, next, options){
    var sliderList = jQuery(this).children()[0];

    if (sliderList) {
        var increment = jQuery(sliderList).children().outerWidth(true),
        elmnts = jQuery(sliderList).children(),
        numElmts = elmnts.length,
        sizeFirstElmnt = increment,
        shownInViewport = Math.round(jQuery(this).width() / sizeFirstElmnt),
        firstElementOnViewPort = 1,
        isAnimating = false;

        for (i = 0; i < shownInViewport; i++) {
            jQuery(sliderList).css('width',(numElmts+shownInViewport)*increment + increment + "px");
            jQuery(sliderList).append(jQuery(elmnts[i]).clone());
        }

        jQuery(previous).click(function(event){
            if (!isAnimating) {
                if (firstElementOnViewPort == 1) {
                    jQuery(sliderList).css('left', "-" + numElmts * sizeFirstElmnt + "px");
                    firstElementOnViewPort = numElmts;
                }
                else {
                    firstElementOnViewPort--;
                }

                jQuery(sliderList).animate({
                    left: "+=" + increment,
                    y: 0,
                    queue: true
                }, "swing", function(){isAnimating = false;});
                isAnimating = true;
            }

        });

        jQuery(next).click(function(event){
            if (!isAnimating) {
                if (firstElementOnViewPort > numElmts) {
                    firstElementOnViewPort = 2;
                    jQuery(sliderList).css('left', "0px");
                }
                else {
                    firstElementOnViewPort++;
                }
                jQuery(sliderList).animate({
                    left: "-=" + increment,
                    y: 0,
                    queue: true
                }, "swing", function(){isAnimating = false;});
                isAnimating = true;
            }
        });
    }
};

#home-carousel-container {
    position: relative;
}
#home-carousel {
    overflow: hidden;
}
#home-carousel ul {
    margin-left: -143px;
    padding: 0;
    position: relative;
}
#home-carousel li {
    float: left;
    height: 645px;
    list-style: none outside none;
    margin: 0 3px;
    width: 256px;
}

As per my comment.

You have set a negative left-margin on your carousel causing it to hide half of an image. As a result when you click next/previous, it shows where an image is moved to create the continuous affect.

Witihin your css, I changed

#home-carousel ul{
  position: relative;
  padding: 0;
  margin-left: -143px;
}

to

#home-carousel ul{
  position: relative;
  padding: 0;
  margin-left: -3px;
}

And had no problems what so ever.