I put a fresh battery in my bike on Monday. After a bit of time, it started right up and ran just fine. On Tuesday morning, it failed to start. I eventually fouled the plugs trying to get it to start up. Yesterday, I took it apart and cleaned the plugs off, and it started right up again and ran just fine for a quick ride around the area. Today, I went back out and tried to start it again. It started up and ran a little bit, and died. After that, it wouldn't start at all, regardless of how much choke I give it. I stopped trying after the third or second attempt that gave me a bunch of backfires. I can hear some combustion going, but it's not enough to get the engine running.

Any ideas on what's wrong?

 

Get some new plugs. And fresh gas.

 

^ Agreed, and how cold is it while your trying to start it? Bikes with carbs dont like the cold. Get new plugs and if its say below 50 degrees make sure you let it warm up to at least 110 degrees before you rev it. If you fire it up and rev right away you will foul plugs.