It's called selling on consignment, and while it does have many advantages (walk-in traffic means more potential buyers see your bike, dealership sales people handle the questions and looky-lou's so you don't have to, the dealership can handle paperwork and financing requests, etc.), you will not be guaranteed a better outcome. Some dealers will do this for reasonable flat rate fees, others want a percentage of the sale price plus inspection fees and other fees that you will pay whether they sell the bike or not. Make sure you fully understand your potential costs if you go the consignment route, and also look into any restrictive clauses in the agreement. For instance, all price negotiations must be expressly approved by you, and you want the ability to cancel the contract whenever you want. If it becomes obvious the dealership isn't really trying to actively sell the bike, you don't want to be stuck leaving it with them for the remainder of the prime selling season.
In other words, with the right dealership consignment can be a great way to sell your bike. But don't assume all dealers are above board and won't try to rape you.
Jerry