I have a Honda Sabre 1100, it had a similar locking gas cap as the stryker. I took a Kuryakyn flush mount gas cap made for a HD and adapted it to fit my bike. The bung has threads and made to screw right in to the HD's gas tank. Looking at the stryker's tank you would most likley have to trim down the height of the fill neck a bit, then take a set of calipers to measure the inside diameter of the fill neck. Then just take the bung to a machine shop and have them machine the threads off of the bung. The bung will slide right into the tank. I actually took the tank to the machine shop and let them measure the inside diameter of the neck so there was no question if they screwed it up it would be on them. To secure the cap to the tank you use something like JB weld or Metal set. This will work with most types of gas cap, bung combination where the bung is made to thread into a tank. It is important to know how your tank is vented, either the tank has a vent tube or the cap is vented. you will need either a vented or non vented cap depending on this. I attached a picture of a couple of different types of caps that could be used.