Ok what you are getting is called BOGGING it is either to MUCH AIR AND NOT ENOUGH FUEL or NOT ENOUGH AIR AND TO MUCH FUEL.
You either have a AIR LEAK or your carb is not adjusted correctly.
So first thing is make sure the INTAKE MANIFOLD has no cracks the CLAMP holding the Carb to the INTAKE MANIFOLD is tight as well as the CLAMP HOLDING THE AIR FILTER is tight. Check if the AIR FILTR TUBEING has no rips or your Air Box has no open holes were a hose would go on.
If all that is good then try adjusting your carb like this:
Alleyoop
ADJUSTING YOUR FUEL RATIO SCREW:
FOLLOW THIS PROCEDURE, take your time DO NOT Be turning the SCREW fast and wait in between turns otherwise you will be off.
VERY IMPORTANT: Warm Up the SCOOT for at least 5 minutes at IDLE.
YOU WANT THE HIGHEST IDLE OUT OF THE FUEL RATIO SCREW YOU CAN GET, TAKE YOUR TIME.
ADJUST YOUR FUEL RATIO:
1. Turn the Fuel Ratio Screw Counter Clockwise 1/4 and wait 10-15 seconds to allow the engine to catch up with the new setting.
** IF ON THE FIRST TURN IT DOES NOTHING OR IDLE GOES DOWN- GO to 2.*** Otherwise GO to a. below.
a. If the IDLE GOES up repeat 1.
b. If the IDLE does not go up or it does nothing turn the Fuel Ratio Screw 1/8 Clockwise that should be the highest IDLE you can get out of the Fuel Ratio Screw-- GO to FINISH UP.
2. Turn the Screw Back 1/4 and GO to 3..
3. Turn the Fuel Ratio Screw Clockwise 1/4 and wait 10-15 seconds to allow the engine to catch up with the new setting.
** IF ON THE FIRST TURN IT DOES NOTHING YOUR PILOT JET AND OR PASSAGES ARE CLOGGED*** GO to CLEAN CARB*** Otherwise GO to a. below.
a. If the IDLE GOES up repeat 3.
b. If the IDLE does not go up or it does nothing turn the Fuel Ratio Screw 1/8 Counter Clockwise that should be the highest IDLE you can get out of the Fuel Ratio Screw-- GO to FINISH UP.
FINISH UP:
SET IDLE USING IDLE SPEED SCREW:
USING the IDLE SPEED SCREW set the Idle to 1500-1800 where it IDLES the smoothest AND the REAR WHEEL IS NOT Spinning-
TEST YOUR ADJUSTMENT:
Now while on the Center Stand GIVE THE THROTTLE a GOOD QUICK TWIST and Let go,
It should REV UP with with a nice VROOOOOOOOOM with no Bogging or Hesitation and Come back down to where you set your Idle.
DONE RIDE SAFE.
CLEAN CARB:
Take Carb Bowl off and clean Pilot Jet and Pilot Jet Passage and Main Jet and Passage.
Then come back and repeat this procedure.
Here is what your carb may look like with labled parts of the carb:
THIS IS THE LEFT SIDE OF THE CARB:
THIS IS THE RIGHT SIDE OF THE CARB:
THIS IS WHAT IT MAY LOOK LIKE AROUND YOUR CARB: