Yes, of course! About 70% of our pedal powered cargo bikes eventually have electric motors installed to help with heavy loads and growing groms. For the Kombi, both hub-drive and mid-drive motors will work. Here are some quick measurements that will help you on your search:
Front hub spacing: 100mm
Rear hub spacing: 135mm / Rear wheel diameter: 24″
Bottom Bracket shell width: 68mm – English thread
You will need to visit you local bike shop or installation of your electric kit. Of course you should begin this conversation with your local Yuba Dealer, as they will be able to answer questions in detail about your specific model.
Just in case: https://yubabikes.com/locator/