Troubleshooting Engine Knock

[andrewg187]

Hey everyone, first off, i apologize in advance for the long the post but, like many, i'm experiencing an engine knock in my 06 GS500F and am in the process of troubleshooting. 
I've read other posts and researched online but so far nothing has produced any results so please let me know if anyone has any thoughts as to where i can go from here because nothing seems to be out of the ordinary..
just trying to figure out the issue and if it's dangerous to ride with..

Sounds like the bikes in these videos:
https://www.youtube.com/watch?v=JkpQhPIPyjM
https://youtu.be/nL_zlQoISYw

i meant to post my own video but the bike is currently torn apart and apparently forgot to hit the record button on the video i THOUGHT i recorded prior..  I'll post a video of the knocking once i get it back together..

the knocking also occurs when in gear and in neutral but is prominent at idle.
it continues to knock in lower RPMs when taking off from a stop but goes away in higher RPMs and speeds.

what i've done so far to attempt to resolve it:
1. replaced spark plugs
2. fixed vac leaks in carbs and intake boots.
3. measured valve clearances.
      Exhaust valves are both at .076 mm
      Intake Valves are both at .038 mm
4. checked all valve buckets which rotate with ease
5. checked starter clutch and it's tight. bolts all seem fine.
6. tilted bike on its side to the left and right and the knocking is persistent at all angles.

Questions I have:
1. The following valve measurements seem to be in spec if i understand correctly.. Would anyone suggest adjusting the clearances based on these measurements?
  - Exhause L&R: .076 mm
  - Intake L&R: .038 mm
2. The Left Intake valve is tighter on the right edge of the valve than in the center of the valve. (see pics linked below). Is this a concern?
   - https://goo.gl/photos/4SVTakus91Vxap6P6
3. The following shows the play in my camshaft. is this a concern?
   - https://youtu.be/60zS_7e884o
4. The following shows the play in my cam chain. Is this a concern?
   - https://youtu.be/qBYUmOrJhGw

[J_Walker]

mine makes that noise, has been for the past like 5000 miles. pretty sure its just means the engine is finally broken in...

if you really care, could be valve slap, or cam chain slapping about, check the tensioner.