Under hard acceleration, it could be excess HC (unburned fuel) and/or NOx. An observer may be able to tell you based on color and smell.
Look at the spark plug porcelain for small specks that might be aluminum. That would indicate detonation under hevy load even if you didn't hear the rattle or ping.
Get the idle and centrifical timing figured out. Then you can work on air fuel mixture. Then you can tweak the timing and retweak the AFR as many times and ways you are willing to investigate to find improvements. My suggestions for a procedure to Tune for Performance.