Not sure if you posted your phone number or email in the ad. There are programs that sniff the net which can pull the email addresses and phone numbers off of your classified ad. Best advice for a Class Racer ad is not put your contact numbers in the ad. Ask interested parties to PM you. It does make it difficult for sites like CL, eBay and Racing Junk for your ads. I got a few of them and told them to pound sand. I wasn't in the mood to d--k around with them. If you do want to have a little fun with them, here is a site that talks about some fun they have had with the 419 scammers. What you have experience is the same thing, they have just transitioned to the next subject of the con (i.e. foreign lottery winner, your family/friend trapped in a country, black money).
http://www.419eater.com
Grab a bowl of popcorn and a beer and enjoy the read...
Some of them are pretty good scambaiters