I've got a 2000 drz400. The bike sat for 3-4 years before I bought it. The jets were clogged, so I rebuilt the carb, cleaned the gas tank, changed all the rubber, and the bike ran great. I used the bike for commuting to work daily, never had a problem. Then, I was heading home after an 8 hour shift and the bike lurched forward a few times, lost all acceleration, and backfired severely. There were flames out of the exhaust. Since then, I have re cleaned the carb, but the bike won't run. It will whine the starter, but never catch. If I spray carb cleaner into the intake it stumbles for a second, then dies. I checked the carb, cam chain timing, and compression. i also replaced the spark plug. Any thoughts?? I feel like its a fuel problem. I pulled the plug today and it barely smells like gas.