i put a 40mm pulley on the motor. made it a lot easier to get used to the machine.
https://www.ebay.com/itm/124309601543?var=425199910545
in addition to having speed reducer. no expert here.
was purchased on ebay. to be fair the seller did not mention Coates in ad. other sellers are. after sewing a few inches on Cobra 4, left end of machine covered in lint.