engine trouble

i have a giovanni motorsport bike. its 49.9 cc, and a lot of fun. it ran real well when i got it, but now, it is very strange. when i go to give it throttle, it will start to choke out if i do it too fast. it takes a while to get up to "top speed" (it does go faster, but this problem slows it down a bit) and then after a little while it will try to kill itself. i dont know what the problem is. if you could help me out this would be great. thanks for all the help! P-Punkie

have you been running the same fuel mixture or changed it and have you ever messed with the carb and try to let your bike warm up for a 1 or 2 min before you ride

Clean out your carb and change your plug use a ngk plug.

where can i get an ngk plug and what size/# do i need? i will clean my carb out though, i think that may be the problem. and tips on best way to do it? TIA

clean your carb with either petrol or carb cleaner

heres the list of plugs you can use... How-To Choose the Correct Plug For Your Cag

Replace the cheap china fuel line with a real fuel line then replace the inline filter and do a quick clean to the carb. You will also notice a small hole on the gas tank lid. Make the hole a bit larger because vapor lock will cause the bike to choke itself also. The problem at top speed is likely to be jetting. Purchase a 68 jet or move the e-clip one notch down from stock to supply more fuel at top end but remember more fuel will also require more air in so either modify your stock air box or purchase an aftermarket filter kit