I have a Trane Furnace BLU055E924B1 made in 1985. It seems to run OK, lights every time, and keeps the place warm. However, when I remove the upper access panel, I can see the pilot light lit, and when it lights off i see the flame run down the full length of the burner on the left. The right does not-the flame just kind of flares up around the burner near the pilot. Is this just a dirty burner issue? Is there an easy way to remove and clean these? Thank you for your help-it is much appreciated.