I lost my key. Is there anyway I can get a replacement just from my bike serial number?

Yours isn't in the database. Contact them direct.

Schwinn Serial Numbers Tool - Vintage Schwinn Bikes

https://bikehistory.org > serial-number

Vintage Schwinn serial number lookup. Enter your Schwinn serial number in the box and click button to see what date and year your Schwinn bike was made.

Register your product - Schwinn Bikes

https://www.schwinnbikes.com > product-registration

Register your Schwinn bicycle with us for up to date information on your model and, if your bike is ever lost ... Product Serial Number* question mark icon.

There is no serial number that short, and bikes can't be ID'd by serial number alone anyway. If head badge and decals are missing the bike is not worth much, and you don't need to know brand/model/age to work on it. For more info see my tip:
How to determine the year value etc of your bicycle

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

If there is no head badge on the front of the bike it's almost impossible to identify a bike by serial number alone, and it's not very important on a repainted bike anyway. Please refer to my tip below for more info.
How to determine the year value etc of your bicycle

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

Normally with the serial number and proof of ownership of the bike the dealer can provide a new key.

Go to HD dealership with bike serial number and order a new key

bike serial number(from the dealer)
or remove switch and take to lock smith

Take proof of ownership and your serial number to your dealer. They should be able to make you a key. If they cannot, you can purchase a replacement switch and key. Hot wiring the bike is never a good option.

get the serial number off the bike and bring it with you ownership papers to a kawi dealer and they can order you a new key. Cheaper then replacing the ignition.

You need to go to the registration branch and get a statement that says you are the owner with a photocopy of your license and the VIN number of the bike. Then ring the dealer and ask if thats all they need and if they are willing to send a key.

To order replacement keys, for small chests and files, you will need to know the key numbers which can be found right around where the key goes in. It should be a stamped number, letters, or both located around the keyhole. For Personal, Home and Home/Office Safes, you will need the model number and serial number. I think that the most economical place to buy keys is from www.SentrySafeShop.com. You can do a search for "lost keys" and it will give you a screen where you can enter your model number and key number. (It is a very easy screen to use. They just need 1.)Model # and 2.)Serial or Key #.)

In Summary:
For Small Chests or Files: A lock reference number is required. It will be a letter, a number, a letter and number, or "blank" (no letter or number), engraved/located on the silver cylinder of the lock. These are model numbers 0500, 1100, 1170, etc...

For Personal, Home and Home/Office Safes: (model numbers will begin with: S0, S3, S4, S5; I0, I3, I4, I5; A3, A4, A5; J3, J4, J5; L0, L3, ,CS,CSW,DA,DS,KS,KSW,MS,MSW,OA,OS,and SC): Indicate your model number and the safe serial number found on the front right-hand side of the door, between the hinges.
Here is the direct link to the key replacement screen: http://www.sentrysafeshop.com/Keys-Sentry-Safe-Replacement-Keys-p/keys.htm