I was going down the highway and the bike just shut off down shifted a couple times, to pop start started right back backfired really loud, then it was fine any suggestions?

 

I can't speak for later models, but my model has a fuel strainer in the gas tank (I have a '94).
If that fuel strainer gets clogged up, then it may still allow gas to flow through, but at a reduced rate and not enough to keep the engine running at higher speed.
You'd be able to get around in the city, but at the highway, it would cut out.
That may be one possibility.

 

Could be a faulty regulator, the symptoms are very similar, the back firing is because the power was shut off mid cycle, so there is unburnt fuel in the exhaust.