660 fuel issues, have questions

[10sec89]

I have a 03 raptor 660, never had any trouble with it until I let it sit for about 6 months.
I will say the fuel in the tank was older than that. I went to start the bike and it lit right off but ran horrible. I drained the old fuel from the tank, pulled the carbs, disassembled the carbs and cleaned everything in and on them, also blowing out with compressed air. Reassembled, put in some fresh fuel and it still runs the same.
The bike will barely idle and sneezes back through the carbs. If you go to rev it it has a dead spot and then will rev but it cracks and pops out the exhaust. Once it's warm if you put the choke on it revs the bike up so all signs point to a lean condition. Also pulled the petcock and cleaned the screens , don't know what else to look at. All the valves are in adjustment as well.
One thing I do find odd is that while it is running bad the reverse light on the barclamp will flash at a steady pace almost like a car with a code.
Any ideas as to what could be causing my lean condition, or the reverse light to flash(thats new never seen it do that before).
Help please!
Than you for your time!

[#17YFZRACER]

my buddy has the same problem and if anyone has any ideas that would be good. i think its some kind of sensor issue

[hotshotgoal30]

bad ground on the reverse. under the tranny there is a nuetral safety switch and a reverse switch and somewhere down there is a little ground that can easly come loose or pop off. how do i know? well i rebuilt a raptor over the winter. reassembled it and it would fire up perfect. it idled beautiful. as soon as ou gave it gas it would backfire and pop. so i did all the same things of cleaning carbs and valves with no luck. started doing some wire testing and while it was idling i touched that wire with the test light which grounded it out and i could rev it beautiful again. i didnt know what it was for at the time so i made a makeshift ground and rode the machine like that. come to find out the machine thought it was in reverse which is why it would backfire because its limiting itself just like you would beif you were in reverse actually moving. its worth a try to see if you have the same problem

[dvx440/440ex]

check ur vent lines around the air box my brother had the same problems had it in the shop for months just to find out one line was pinched runs like a champ now