Aftermarket Primary Tentioner

I am wondering if any of you guys have/know of an aftermarket tentioner for my primary. I currently have a snowmobile chaincase tentioner but the mounting is a bit of a problem and eats tentioner springs fairly quickly. How do you guys feel about the original setup? My bike is far from show quality so I look more at functionality.

Thanks!
Dave

I believe Fred at Old Britts has one that he fits along with his belt dtive kits. Not sure if it's compatible with chains though..