Re: Newbie questions for upgrading
Once you have run at least three tanks of fuel through it and the engine is fully broken-in. it's time to jet it properly.
Most china dolls come FAR too rich from the factory and tend to four stroke badly on top end.
Try dropping the main jet size down. (Most of mine have wanted at least two sizes smaller, sometimes three)
I can't tell you the numbers since I solder and drill my own jets using wire guage bits for consistency. You buy five jets labeled .70 and you often get four or five different size jets. Drilling them is easy and free.
Remember, if it only four strokes at full throttle, you are on the main jet only. If it pulls hard to the top then blubbers and four strokes, drop the main size till it pulls hard all the way to your rev peak. Don't forget to reset the needle with all main changes for max tuning range. I drop a jet size, then start from full rich on the needle, Checking one slot at a time until the engine feels happiest.
If more is better, then too much is just enough.
If you can't afford it, build it yourself.