Focus your time on people who want to join. If your friends need to be "motivated," leave them alone for now and focus on building your business. Your success will be all the "motivation" they need.
Make a move. Contact them through E-Cards, X-Cards, or via e-mails. Show your Payoneer Mastercards, if you have one. Be able to let them see the reality in SFI by always sending e-mails.
Keep posting your products in your social network(s), and show them the job your doing. Post your business on a Friday, the weekends are the best time and they might check it out in their spare time. You can never force another person into a business, but they can see what you're doing for yourself. They'll think about you giving them the opportunity when you're successful in this business.
One way you can motivate your friends to join SFI is to give them the tools to succeed. No team will stay motivated if they do not have the necessary tools required to do their job. This includes; internal support, inventory, marketing materials, training, etc.