I need to make a small adjustment. I have a Centaur Double with 39/53 with a 10 spd cassette. For some reason I don't think the bike is getting fully into high or fully into low all gears in between shift fine. How do I make the adjustment.

Hi and low limit screws on the RD. Assuming you really have a problem. www.parktol.com repair section has the drill. Too loose a low limit will get the chain into the spokes. Too loose a hi limit will drop the chain off the small cog to the outside of the cassette. Adjust in very small increments.