Originally Posted by Eddie25
Any ideas how to improve this? I recently serviced it and my brother had a look at the spark plug and said it's running way too rich. I'm not too clued up but i know i can play around with the jets. Im at sea level in a warm climate. Standard jet i read up is a 107mm will re jetting to a smaller say around 103 work? Or even smaller. Or is that just what is to be expected from these scooters?
I think you are on the right track.
If the plug is black, and not tan, it would indicate a richer than optimum overall mixture. Also check that the air filter is clean and the intake is clear. Temporarily running without the air filter would lean the mixture, and may tell you if it will run better if tuned leaner.
Sometimes finding parts for the Chinese engines (carbs) can be challenging, but usually they are a direct copy of one of the more popular brands. Jetting takes some trial and error to get right, but I would expect better number than you are getting so something isn't right.