I had to edit that link because I'm still learning to operate this thing.lol
Here's a link to a good discussion on chain tensioners; http://motorbicycling.com/showthread.php?t=56080
I prefer to not have one. Others do. There are some really good alternatives to the kit tensioners, from bolt-on to weld-on. And on some builds, they are necessary.
That's too bad your gas-bike is in the corner, hopefully soon! I've been riding here in Montana, winter has been pretty mild.