You most likely can. Make sure that your frame dimensions will fit the requirements for the kits/engines you look at. You may have to modify your mounts a bit to make it fit correctly. A welder, some bolts, and a drill will help immensely there. Make sure that your chain is long enough. Since you have a larger diameter wheel, you may need to buy some extra chain and connect it with master links. Since your wheel is larger, you may get a higher top speed out of the bicycle, but keep in mind that it will slightly affect your torque.
Now, this is from a novice at motorized bicycle building. I'm sure the more experienced builders on this forum can add and subtract from above.
Have a good one!