I have a Rex 607 Z and I replaced the stock flywheel with a Sailrite Monster wheel. (Amazon was out of stock on the 'Cuda Crank'), The Sailrite Monster Wheel is great! More torque, the extra sprocket and belt reduces the linear sewing speed and adds even more torque. My Rex 607 Z modification's resultant performance is leaps ahead of the stock flywheel.Has anyone replaced the flywheel on a 607 with a sailrite flywheel?
My Rex 607 Z machine also had a low foot height so I found a Sailrite video entitled 'Setting Foot Height & Range of Motion Between Inner & Outer Foot'. ( ). My Rex 607 is now ready for business.
Hope this is helpful.