bogging out at certain rpms is a fuel flow issue. So you're on the right track. Trace your fuel system to be sure your lines are not kinked, clamped, dried etc. Check your tank for debris on the screen and check your filter.
That said, 1-6krpm, 10krpm have the pilot jet in common. Check your carbs to make sure these are not clogged with debris. 10k you should also be looking at the main jets for clogging.