That's a cool pic Knolly. When I showed up at tech inspection they were like uh uh, not because of noise levels but because of no muffler.
While waiting for Brock to finish the full exhaust I ran for a short while w/ the same thing, just the muffler removed. It's loud but honestly that's all it is, loud,,, sounds like junk compared to a full system without the Cat.
I didn't know you would even try running a bike like this without the end can of some sort. Yes I believe it wouldn't run ideal as it would be designed to run with some sort back pressure, but I wouldn't think it would damage the engine. After all some exhaust systems are straight through with virtually no back pressure, but these are tuned to the engine normally. The US is really cowboy country huh You would get shot here riding on the street like that.
Good luck with the new bike!