Hello NEW Bob, Big welcome to the forum! If your a true 140 a 35 tooth or maybe even a 33 may work even better...hmmm not sure you may lose too much torque though...?
Best source for a steel sprocket I found was:

http://www.jtsprockets.com/61.0.html
and plug in the JT sprocket tooth count at the end of the stock number.

For example of a 35 tooth stock number that fits is jtr279.35 they take paypal also. Mine came in just a few days.

NEVADA BOB has the exact bike.