Mike:
Look on the Reese Hitch site,
http://www.reeseprod.com/. You're looking for part # 118352. This is the "T" connector for our cars.
Determine the class of hitch that is installed. I have seen alot of class 1 hitches on these cars that will limit your towing weight to under 1,000 lbs. Don't know what your bikes weigh but I would guess the two of them are over that. Don't forget to add the weight of the trailer. Would venture to guess the value of the bikes, far outway the value of a new hitch.
When ever we are on the road during "Bike Week" at Daytona (on our way to Florida in the spring) it never ceases to amaze me the number of $30 to $40,000 motorcycles being towed by 500 dollar rust buckets and old junk trailers. Scary when you think about it. If you can afford the cost of these motorcycles, at least spend some dough on something that will pull them safely.
Class 2 and 3/4 hitches are still available for these cars and would make a better choice.
Bill