I have to push my bike full speed down a hill to start it (clutch start)?

Take some sandpaper and clean the pick-up's for the magneto, that and a new plug wire will straighten out the firing problem, it also sounds like you should check the reed's out they may be split.

charge the battery, or replace it... before it explodes... as they do...

bad ignition coil

get a new battery and pour sea foam in the gas sea foam should be right at wal mart

try to clean out the carburetor

If it runs well once started, then its most likely one of the following: Battery Starter Motor Ignition Switch Depending on the model, it also could be something like the neutral safety switch, which on most bikes prevents the starter from getting power if the bike is not in neutral (prevents you from starting while in gear, which would cause the bike to lurch forward if the clutch was not squeezed in). To rule out the battery: Turn the ignition switch on, and note how bright the headlight is. If it does not go on, or if it is very dim, then you're probably looking at a dead battery. (The old test for cars used to be to wait with the lights on for 10 minutes and see if they are still bright - bike batteries are small, you might not want to wait that long). If the battery is bad, you should be able to jump start the bike by using jumper cables connected to another bike or a car (as long as they have the same voltage, it should be fine). If the bike starts when connected to another vehicle via jumper cables, then you know that it's just a dead battery. If I was going to test the starter motor, personally, I would make sure the bike is in neutral, on a center stand, with the back wheel off the ground. Then, I would locate the starter motor, and connect a meter or test light to the positive terminal. If it shows power when you hit the starter button, it tells you that it is getting power. If the light doesn't go on, then it's probably a safety switch (like neutral safety switch, clutch safety switch, or sidestand switch). You would locate each one, and try jumpering them. At some point, the starter motor will engage, and then you've found the faulty switch.