I remember the first time I got my bike I had it running for about 3 days after the third day it started running funny. The next day I went to ride and I didn’t even make it out of my yard before my bike shut out and wouldn’t start back, I waited till the next to go and start working on it, when I went to open up the engine I realized that the carburetor was loose and was almost falling off. I cleaned the carburetor and tightened it and the bike started with one kick, but after it started it still felt like it was lagging so I checked everything, I checked the magneto the coil and the spark plug everything I checked had looked right but it was still lagging, so for a next 25 minutes I just looked around and still couldn’t find out why it was lagging. I just couldn’t figure out what the problem was so I just left it alone and came back to check it out again a couple hours later. I looked around at the engine again and still couldn’t figure out what it was making the bike lag, but something came to my head and just told me check the spark plug coil. I reached down to touch the coil and it was very slack so it wasn’t pushing enough electricity through the bike and I looked at the plug and it was dirty so I cleaned the plug and tightened the coil and the bike started and stopped lagging.