I've noticed my chain is getting broken in and has streched a little. So naturally it needs tightened, but how. I know that the rear suspension needs compressed to make the swingarm parallel to the ground and then you loosen the ecentric bolts. But do you need a special tool to turn the ecentric and how much slack should there be in the chain and where do you measure it, middle? top or bottom? Isee a lot of talk about changing sprockets and adjusting chains so I know somebody out there can help me. Thanks.