I bought my pulley from an industrial supply house named Mcmaster Carr ($3.50). The small pulley available is the correct pulley for the L3 belt that was used on my Pfaff1245. The belt cost around $5 at a supply house called Motion Industries. The original belt was 48 inches and the new belt is 44 inches. Again, the belt series is an L3 width. This is standard for 3/4 inch ID pulleys, one would have to go out of the way to obtain a 13/4 inch OD pulley with a 3/4 inch ID that uses a 1/2 inch belt.
So how does it sew? I find that I am better able to control the materials I feed into my machine, and the seam is much straighter as a result. I plan to convert my Juki dual needle as well, it sews far too fast, uses the same 3/4 inch shaft on the output of the clutched motor, I have an extrapulley
for my Juki