Jetting usually is a trial and error ordeal. My first attempt after installing a K&N air filter, produced the same result you experienced....any more than 1/2 throttle caused bogging.
After some experimenting, I found that a 115 worked very well with my air filter....scooter climbs hills like a mountain goat....and is still delivering outstanding fuel mileage.....but that doesn't mean this setup will provide the same results on all 150cc scooters.
Don't know anything about your filter......do know most scoots come from factory running a bit lean.....if you go back to your original jet, with a high flow filter, you
will be running an even more lean mixture, and causing elevated operating temperatures.
If you bought one of the jet kits that contain 5 or 6 assorted sizes, I'd try a 110......original equipment is 105 or so.
This is what my spark plug looked like two days ago....not too rich..not running lean...pulled it to do valve adjustment check. Miles on plug..4,501. Miles run with 115 main jet, and K&N filter..4,135. I have not touched (adjusted, cleaned, or fiddled with in any way), the carb or air filter, since installing these parts on June 7, 2012. Like I said...trial and error
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