I have a 150cc Chinese dirt bike. About a month ago it started to bog a lot. It could only start on choke, so I took apart the carburetor, cleaned it and put it back together. The problem still there. It doesn't need to start on choke anymore. The bog is pretty bad with constant backfire and it will not idle (like at all).
The bike doesn't sound the same at all. It becomes really hot really fast and shuts down when I let the gas go. When I try to ride its like it has hiccups. Like there's large pockets of air in the engine. I tried playing with the mixture screws on the carb, but it makes no difference literally.
If I slowly turn on the choke it almost goes back to normal, but backfires badly and shuts off. After that the only way to start is to push start with the choke off and it's back to the insane bog and backfire. There's a small smoke leak from the connection of the silencer and the exhaust connection, but I don't think that's the problem.