The original WC-1 motor has problems with the valve seats. Thousands were spent to find a solution and in the end the answer is to upgrade the cylinder. Whizzer offered a kit for $466.10 plus shipping, however the kit contained several parts that were problematic. I have helped hundreds of Whizzer owners get their WC-1 motors running perfectly, and can usually help for less than the kit option.
If you can buy it for $500.00 I would suggest you purchase it right away, because in the end you would have less than $1000.00 invested, and a good running Whizzer is worth far more than that. Because of serious quality control issues on the latest models the older bikes [1999 to EARLY 2008] appear to far more reliable. I have many new edition Whizzers that I ride and many have over 6000 miles on them. I live in NC so I can help you if needed. I doubt you will exceed anywhere near 1000 miles with the original WC-1 motor, but who knows. Most usually quit between 450 to 650 miles, but I have been told [never seen one] that some have made it to 1000 miles before the upgrade is needed.
My advice is to buy it, and I can help you make it "bullet proof". I have lots & lots of Whizzer parts in stock, including parts for the original Whizzers [1939 to 1962].