Ping goes the weasel

My brother was cruising around on his new to him VFR, when at freeway speeds his engine sounded like a box of rocks.  If he got aggressive, it would go away.  It only did it when at normal operating temp.  The pinging was so bad that he hesitated to maintain speed, and quickly exited the fwy.  The bike has 20k miles, mostly stock except for a Two Bros. silencer and a stage 1 jet kit.  I'm kinda bummed that my bro had a less than positive experience with a VFR.

And the previous owner was an engineer, and the bike was dam close to spotless for 20k miles.

I'm going to ride it tomorrow to see what I hear, but I am very open to suggestions for possible issues.

He and I both have different ideas, but I don't want to lead the jury.  Let me apologize in advance for the lack of details.

:ohmy:   hopefully you get it figured out!

I would guess a bad ignition advance or bad gas.

Wrong gas? It takes 97 octane, right?
Good luck.
C

I rode the bike for about 30 minutes today, and fortunately I did not hear anything bad.  That doesn't mean that it didn't do it before though.  I'm leaning toward less than ideal gas too, especially because we don't know how old that gas is.  I really hope this issue doesn't pop back up.  Thanks for your help, everyone.  If it happens again, I'll let you know.

Yes, please go through a couple tanks of good fresh gas. Maybe a slpash of carb cleaner in there too for good measure? These engines are pretty tough, so I would be surprised it is falling apart on you... Now, go riding to burn that gas!   Doctor's orders!!!
C