Wont fire

[Bamabrat]

Rode to work today w no issues. Sick, so went to leave at lunch. When I hit the starter, the bike had a pre-ignition pop then slowly cranked for 3 seconds before dying. Tried again. This time, no fire. The battery is strong, so that's not it. Spark plugs are connected well. Have tools so removed tank. Couldn't find a vacuum line loose or broken. I could hear a lit of air when I was trying to crank it.

Can't do anything now so leaving bike. This is my main mode of transportation. Any ideas are appreciated. Will come back tomorrow with several options (hopefully) on how to fix it.

Background: 2001 1500, 44k miles. Carb. stock intake (still have dual dog bowls). Cobra exhaust. Never had an issue starting. It doesn't like cold, but with choke, takes 4-5 mins or less to warm. Every now /then have a single pre ignition pop and smell fuel. been using 93 fuel and read a thread saying it could cause the pop. This tank, changed to 87. Have 90 miles on the tank. Normally fill up at 110 (I have the small 4 gallon tank). Avg mpg is 38. Every 4th tank, use an additive in fuel to remove Crap. Can't remember which.

Yesterday, replaced rear cylinder coolant/water pipe oring and used silicone to ensure no leak. It didn't on my way here. Also siliconed cam plug. Not leaking either. Removed tank, both bowls and plastic air tube to get to water pipe. Added coolant, brake fluid, and put gas back in tank. Ran like a champ this morning.

Any ideas please. I need some help guys. I live 1 hr away from my bikes current location

http://s1296.photobucket.com/albums/...psa3dd2905.mp4