High RPM and Harley usually doesn't happen. I've ridden metric bikes before my ironhead, its rev limit is really low. Its underpowered, old generator bike with a tiny battery. I wouldn't change it for anything. Its just fun to ride. Everyone has an opinion I try and keep it as quiet as possible in residential areas and rarely ride through them if ever. I do enjoy the 38MPG I get and just being on a bike. The work commute is more pleasant on my bike. My landlord has a 2 year old, my loud bike doesn't ever wake them up when I leave at 530 for work. I just ride nice. The bike is not going to set any speed records, I want it to last a very long time so no reason to beat on it.
That said yes to accelerate in the heavy underpowered bike at any reasonable rate it will be loud. 6 seconds wouldn't get me from a stop to 45 MPH hahaha