Ah, yours is different than mine. Mine is a 120-491, I should have looked closer at your pic. It has a different drive wheel than mine. Mine actually has a bobbin winder on it.
What size hose did you use to make your rubber tire with?
If your owners manual calls for a Kenmore 49 needle like mine does here is a trick to make setting the DCx1F easier. Take a strip of magnet tape and cut out a tiny spacer. Put the spacer in the needle hole and push it up with the needle. Being a magnet it will stay there and you can switch out needles easily.
Joe