Q:

Is it a bad idea to buy a motorcycle with a lien on it? 

I was curious why is it considered a "bad idea" to purchase a motorcycle/vehicle with a lien on it?  
It started when I came across an ad on Craigslist where I'm interested in buying a used vehicle.  However, the seller mentioned that there is a lien on it.  When I searched what a lien was, many people mentioned that it was a really bad idea to buy something with a lien on it, without going into too much detail why.  
From what I understand so far, a lien is basically an asset that is owned by an individual but that individual still owes money to a lender.  Why is this known to be a "really bad" or "avoid at all cost" type of deal (which was the general consensus)?  Can't I ask how much there is left on the lien and negotiate that into the final price? 
Update*: I purchased the bike.  Pretty simple (so far), I went to the seller's credit union and paid the bike's lien with my cash.  The bank clerk signed off the lien on the title and then the seller put my name on the title.  I just need to take the title and change it to my name (I'm holding onto the original title and bike).  Thanks to all who helped!  

A:

In the case of a vehicle with a lien, there is a specific place on the title to have a lien holder listed, and the holder of the lien will also hold the title until the lien is cleared. 
Usually this means you have to pay off the loan when you purchase the vehicle.  If that loan is held by a bank, meet the seller at the bank and pay the loan directly with them and have them send the title directly to you when the loan is paid.  This usually involves writing up a bill of sale to give to the bank when paying the loan. 
The only thing you're trying to avoid here is paying cash to the seller--who then keeps the cash without paying the lien holder--who then keeps the title and repossesses the motorcycle.  Don't pay the seller if they don't have the title ready to sign over to you. 

A:

It's extra work for you to purchase a vehicle that has an outstanding lien on it.  It's not uncommon, but there are things to take care of and watch out for.  Really, all it means is that the vehicle you're trying to purchase hasn't been paid for in full by the current owner.  Where things can get dodgy is ensuring that all outstanding debts are paid against the vehicle at the time you take ownership of it, otherwise the owners of those debts could still reclaim the vehicle.  
Here's a good article about making this kind of purchase. 

A:

A lien is a mechanism to impede legal title transfer of a vehicle, real property, or sometimes, expensive business equipment.   That's why title companies exist - to make sure there are no liens against something before a buyer hands money to a seller. 
The lien can be attached to a loan, unpaid labor related to the item (a mechanic's lien) or unpaid taxes, and there are other scenarios where this could occur. 
The gist of all this is that the seller of the vehicle mentioned does not have clear title if there is a lien.   This introduces a risk for the buyer.   The buyer can pay the seller the money to cover the lien (in the case of a bank loan) but that doesn't mean the seller will actually pay off the loan (so the title is never clear!).   This article recommends visiting the bank with the seller, and getting title on-the-spot.   However, this isn't always an option, as a local bank branch isn't probably going to have the title document available, though the seller might be able to make some arrangement for a local branch to have the title available before a visit to pay off the loan. 
The low-risk approach is for the seller to have clear title before any money changes hands.