go to your local credit union or your favorite bank and find out what the interest and payments are for a $5500 (or whatever cost the 620 is) loan (for your 620) (unless you plan on putting some $$ down, in which case subtract the down from your loan.
Or, try to figure out how much in cash they're willing to sell you the 620 for then get your bank loan for the cash amount and use the loan to pay cash for the bike.
btw, noticed that the '04 620 has 6 gears standard (dark is 5 speed). the Capirex isn't the only one to have a 6 speed.