Bike wont start and when it does it backfires out of the carb.

[twobullman]

OK, I am a brand new owner.  I've been riding for about two weeks now.  Heres what went on.   I bought the bike and it ran great for a few days, it sat in a rain storm then it wouldn't start, upon calling the guy who sold it to me he said there was a trick to getting it started and i probably fouled out the plugs which in turn killed the battery.  I pulled the plugs out, and cleaned them, and jumped it off and it started and ran.  I rode it for a day and it started giving me trouble again.  I did the "trick" to start it, and it would start, and run for a few seconds until the idle would drop below 800 and it would die.  I kept starting it thinking it just needed to warm up, and it would idle at 800rpm for a few seconds and then die.  Recently it started backfiring out of the carb and idling low and die.  I used the throttle to keep it alive but it was still backfiring from the carb.  I started it a few days ago thinking it might be like a car I revved it to the moon, around 8000 and blew black smoke from the exhaust, and it ran ok for a bit, but then it went back to the same 800 rpm and then dying routine.  I have adjusted the idle on it, and it runs for a bit but the idle will go from 3000rpm, back down to 800 rpm without me touching the throttle.  Now the bike wont even start. 
I need some help!!!

[Howie]

Other symptoms?  What did the plugs look like?  Could you have turned the wrong screw and thrown the carbs out of synch?  What was the "trick" the previous owner told you?

[koko64]

+1 . Stock carbs? How many turns out are the Idle Mixture Screws?
If stock carbs, how many miles on the needle jets?

[bond0087]

I hate to be the phone tech support guy, but it does have plenty of fuel, right? Keep in mind that just because the light isn't on doesn't necessarily mean much. If it was getting inconsistent fuel delivery from a low fuel level, it would cause most all of your symptoms. Also, the act of lifting the tank to check/change things could have temporarily helped because all of the fuel settled back by the fuel outlet. Again, hate to point out the obvious, but I've made that mistake and done much dumber things early on with my first bike.  I once cleaned out the petcock, put everything back together, and then rode off with the fuel line disconnected.  Surprise, surprise, it died a mile later when the float bowls were completely empty.  I fully deserved that 100 degree hot summer walk home in my leather jacket (facepalm). 

Also, just a general tip, throw the battery on a charger overnight before doing a lot of troubleshooting.  Jumping it on a dead battery isn't really the best way to go, and having slightly less than 12V at the battery after the starter load is gone can cause all sorts of mystifying symptoms on certain bikes (don't know exactly how well Monsters do with that). Another thing you can do is take the battery out completely and just hook up a car battery via jump leads instead.  That'll take low battery issues out of the mix.

Good luck, and remember to check the easy/simple stuff first!

[twobullman]

Thanks for the help guys, I got the bike started.  I pulled the plugs, and cleaned them, jumped the bike and started it, let it warm up and it ran fine for two days.  Now it quit running again.  I think Im just gonna hafta take it and have a pro look at it.
I really appreciate the advice though.