125-200cc Cr 125 Engine In A Sms 125 (2012) Frame?

Hello. I recently got a 2012 husqvarna sms with mechanical power valve. The engine i got now doesent have spark, eirher because og the stator or the crap wiring thats on it. Therefore i have thought of putting a wr or a cr engine in it depending on what come out on the market.
I know all the different engines used different wiring so will also have to transfer that over
Will there be any problems putting a cr engine and wiring over to my sms? I know that cr doesent make power for the light but that can i fix with a battery or something
Thanks