Pretty normal for that age of transformer, they do run warm, but if you look at power factor it will show the power factor at no load being almost purely inductive, probably around 0.8 to 0.9 PF leading. You could place a capacitor in parallel with the supply, probably around 8uF 450V motor run or lighting power factor correction capacitor, and improve the no load current, but this will also mean higher inrush current at turn on, though current drawn from the line will be lower overall, though you will still have the current in the primary being the same.