Hey all - I've got a 1997 GS500 that I picked up at the end of last season for cheap, as the previous owner was having issues with how it ran.

Spent the winter working on the bike and catching up on all of the maintenance items, trying to get it to run. 

Replaced spark plugs,
emptied old gas out of tank, put in new gas and seafoam
Pulled intake filter - Was able to get it to start by shooting starter fluid directly into carbs. Would rev up to 6k then die. Playing with choke and doing this, I was able to get it to idle steadily but the moment I touched the throttle the engine would die.
Pulled the carb out of the bike, disassembled it, made sure everything was to spec and flowed properly, replaced screws on outside of carb because they were all stripped out.
Replaced stock battery with AGM, completed oil change and changed oil filter.

Still having the same issue. With copious starter fluid it will start, rev up to 5-6k then die, all over the course of about 6-8 seconds. The last time I got it going I had a backfire so I think it's safe to assume that it's getting air, fuel, and spark.

Any suggestions at this point would be wonderful. By all reasoning I'd have to assume it's a carb issue but I've already completely gone through the carb so I'm not sure how exactly to proceed.

Thank you!!
J

Have you checked the mixture screws? The idle screw? I JUST had this problem. Needed the mixture screws adjusted.

I was told that they were 3 turns out from fully screwed in so I set both to 3 full revolutions when I had the carb out. The idle needs to be adjusted, I'm sure, but I'm not sure how to adjust it without the bike actually running.

Pull out the new spark plugs and check to see if they show any signs of being too rich or lean.