poping from intake

my 76 kz900 is poping out of the intake, and has a bad miss if held at a steady rpm around 5k or so. checked compression and its 130 on all 4. plugs are sooty black. timing is electronic and spot on. had the engine apart last fall repairing bent valves from previous owner. plugs make me think its rich. but that dosent explain the intake poping. i sitll have to check my valve lash again. any other things that might be causing my troubles. thanks.

While in the valves double check the cam shaft timing. Then I would make sure of having proper Ignition spark.
Then it would have to go to the carbs/ fuel delivery, recheck float levels, sync, etc.