No big deal, it's a normal way to sell. What's below is generic. Ask any local car or bike dealer how this works for private sales in the State where you live.
Start by looking at your title to see who the actual lender is. For example, even though a bike may have been bought from dealer ABC and they used "Yamaha credit" the actual bank shown on your title will be something like HSBC Bank and that is what will be listed on your title. Find the nearest one, tell them that you are trying to sell the bike, and ask them their procedure to release the lien. Also ask how long it will take.
Once you know that you can post in Craigslist or anywhere else. Be aware that having a lien will probably mean that if/when you get a buyer, you are going to have to share with them what you learned from the bank. It may take 10 days for the bank to clear the title and titles are usually kept somewhere remote; meaning the title needs to be FedEx'd to you for an additional ~$15.
That's one reason so many ads will state "clear title in hand" or something similar. They've paid off the bank (if there even was a lien) and a buyer can ride away with the bike immediately.
Good luck, as it can be frustrating to get a buyer and lose them because they didn't want to wait. Or have to lower your price for them to wait.
btw - This post is in the wrong area.