Its a long story but this forum helped me get my 2005 DRZ400S running again. I was having stumbling / starvation problems when running at WOT and tried to solve it by setting the petcock to prime thinking it was a vacuum issue. What I didn't realize was that when I forgot to switch off prime while parking it for a few weeks, fuel would leak past the carb into the cylinder. I experienced hydro-lock and after clearing the cylinder (as well as r&r'ing the carb at least 3 times), it still wouldn't run although it would occassionaly start when cold but then die when warm. I finally found several references to a problem where fuel could contaminate the oil and cause these symptoms and after changing the oil and filter today, it fired right up. I will change the oil again after a few more rides and then pray that my engine will be just fine.
Thanks to this site, I didn't have to take it to the dealer ... who knows if they would have figured it out.