Yes they come too lean . Many have the " secret 63cc " engine instead of a 49cc . Run it WOT until you hit top speed and hit the kill switch . Allow it to cool to avoid burning your fingers so you can remove the sparkplug and compare it to this chart
http://www.4secondsflat.com/plug_chart.html
It sucks having the drill out the air fuel screw . Some even have the bowl riveted on . An aftermarket carb you can adjust the needle position where most stock carbs lack the needle clip . Here is a jet kit
http://www.partsforscooters.com/114-...ategory=133078 PFS also sells carbs but they have 4 types listed so you would need to compare and call them first in case you decided on getting a carb .
I would duct tape the crack until I could get a new airbox . A Uni can allow more air but the stock head and exhaust may have some bottle neck . Now if you had this big valve head on the top of the page and a BBK you would have a gain with the Uni once you got the jetting right after testing a few sizes
http://www.scrappydogscooters.com/13...rformance.html Read this thread on the TaoTao ATMa 50
http://49ccscoot.proboards.com/threa...5014=undefined