how to classify E-race bikes

I've been wondering this for some time now. Now after reading about Yate's little run with the gassers, one can't help but wonder how you classify the E-bike. Gasser classes are primarily classified by displacement and/or twins and four cylinders. How does one enter an E-bike in a gasser class? Is there some sort of rules that they have formed that classify voltage or current or motor size or something? I see the EV drag classes have it broken down, will the bikes that cross over have any rules like these.
I first started thinking about this with Killacycle, which is an awesome achievement and I would like to see more bikes like those racing. That thing actually looks like the gasser counterparts that I wish it were racing against. But how long will it take to really shake this bike down to really get to know the potential? Do you just give them an open rule book until they catch up then start figuring out the rules then as needed? I know it will take some time, as NHRA and other car/motorcycle drag racing org's can attest to it takes time and constant altering to keep a level playing field. NHRA likes to keep things close so they police every possible thing there is to police on the bikes. They even have the right to tell which brand cylinder heads you can or cannot run, no custom stuff there.
I personally would like to see electric karts racing against gassers. I have been waiting for the right type of motorsport to take this step with and I think karts will offer the least resistance. My idea right now is to build a 15 hp kart and see where it lands track performance wise and then start the patition to mix with a class of gassers.