pulsing engine sound at highway speeds

[Badbob]

I made this sound go away on my GZ250 buy carefully adjustment of the chain tension aligning the sprockets with a gauge that easily lets me see if the chain and sprockets are aligned properly. I don't us the marks any more. Mine were not even close.

After thousands of miles of riding sound has not returned.

My theory is (No I can't prove it) that the noise was a combination of two things. The fact that sprockets are not perfectly round causing the chain to be tighter in some spots that others and the sprockets not being aligned properly. Its not even my theory really. I ran across this some where else but I can't remember where.