Well, Boris (Boris? Are you a Russian?) if the bike's "pick" or 'acceleration' is fine and you also don't happen to be a "Speed Freak" then why you're concerned about TOP SPEED in the first place...?
Harley Davidson riders are also like you, they care about 'Torque' or 'Acceleration' and don't give a dime about TOP SPEED... Hence, a 1,600cc V-Twin Harley churns out just... JUST around 70HP at the crank! For comparison; A Suzuki SV650 makes 75 even though its just a 650cc V-Twin... A Super Sports like Kawasaki ZX6R with a 636cc inline-4 engine churns out nearly 140HP at the crank! But do Harley fellows care? No, they don't... They just RIDE...
STILL NOT CONVINCED AND WANT TO TOUCH 300KM/H ON YOUR CG125...???
Well, here's something for you, bro:
https://www.youtube.com/watch?v=PIqXBY1yImI
Yamaha R125, the king of 125cc bikes signs-off at around 130KM/H and it makes 15HP, and goes just 120KM/H with the head-up (Just watch the video)... Your CG125 makes 11HP which is just 73% of R125's full potential...
And the 73% of 130KM/H speed would be 95KM/H... I know, it's not a realistic way to calculate top speed, there are so many factors to consider... But when you consider the aero-dynamic shape of R-125, Water Cooling, tight engine tolerance, Four Valves & Dual overhead camshafts instead of CG's push-rods, 100KM/H is about the most you can squeeze out of your CG...
AND MOST IMPORTANTLY, A 4-STROKE 125CC IS A TINY ENGINE, AND THEIR SOUL PURPOSE IS COMMUTING, LET IT BE CG125 OR R125...
Be realistic & reasonable, brother...
Good Day!