I have been riding my bike to work a lot lately and I notice I only use the brakes when I am basically coming to a stop. I mainly slow down via drag or engine braking.
Now I know motorcycles have to be light yadda yadda. But I think they really lend themselves well to hybrids. On surface streets I am constantly pointing, squirting and then slowing down (sorry). There is a lot of opportunity to recapture energy there. And even on the highway, while there’s less stop and go, there are still hills and slow downs.
The battery and motor would not have to be big at all. Battery could just be cells conveniently strewn about the bike, giving just enough juice for some “torque fill”. Motor would just go with the clutch and flywheel. Bike + rider is only 700 lbs... you would not need much electric capacity to get things moving. It would help gas mileage a ton, which could work both ways... something like an NC700x could do like 100MPG... or a Tuono V4R could get more than 30 MPG lol. Would help a lot with emissions too which motorcycles are surprisingly horrible at. Just spitballing here.