RPM on the kick stand would leave the engine very lean and when the engine is under load it probably won't accelerate well at all and could seize. Testing each new setting under a load. Once the acceleration starts to suffer, you have gone to far. It is better to depend on cylinder porting to get peak RPM than on ultra lean mixture settings. Engine Chutters at full throttle and doesn't rev high.
Engine bogs from low speed.
Open it 2 or more turns and tune for chutter. Worn parts, tall gear ratio with heavy porting, high intake duration, restricted exhaust and low cylinder compression can cause low speed bog. The low speed screw is to far open. If idle speed is to fast after adjustment slow the idle down using the idle screw. Engine idles smooth but runs poor under load unless throttle is full open.