Noise.
The noise you hear is from the primary. They all make that sound. Some different types of oil help. I use 20-50 amsoil and it helped but didnot completly get rid of it. As for welding the counter balance gear to the crank, i would give it some serious thought before i do that.
I hear all kinds of engine noise from my 09 heritage. I was told to buy the extened warrant and just drive it. So far the noises havenot got worse. Maybe their right.

Johnny popper

 

The noise disappeared after the 5K service...

 

When i upgraded to 103, at darkhorse...they welded counter sprocket....no problems at 100,000 miles....old motor...cheap insurance