I just put a lunchbox air filter in, and rejetted with 147.5 mains 40 pilots and 2 #4 washers between the needles on my '97 GS500E.  Set float heights to correct specs, and it is running VERY weird.  It will climb at any given time to around 4k then slowly fall down to normal while idling.  Unscrewing the idle screw does nothing, the bike just stays idling at 1.5k until it makes one of the weird jumps to 4k.  It also sounds like sputtering out of the tail pipe.  I've read many posts and am still clueless as to what my problem is.  Any help is GREATLY appreciated.

Someone here will be able to help you. You just need to find out if you're running lean or rich. Also did you mess with the air/fuel mixture screws at all? People usually adjust those.

I think that 147.5 is a little on the rich side. I would sugest that you try 140 mains and 2.5 to 3 turns out on the Idle get. you may also want to take one of the washers out from under the needle.

When putting your carbs back on, make sure that all your connections are correct, especially the intake boots.

yep rich as, im on pods so not quite the same but im on 137.5 now 2 turns out on mixture , get some 140s and try again, it might not be quite right but it'll be closer than where you are now

So try 140s and 1 washer out from under the needle or just 140s?  Thanks a lot guys, I'm a college student so a shop would really kill my already wounded wallet.

tried 140s and its better, BUT it spatters/pops when riding, and the throttle response seems weak(even for GS), it will also want to idle at 3k for no reason? any ideas? I'm stumped

Didnt look like you mentioned this but it seems that you only upgraded to the lunchbox. Now if im not mistaking your suppose to get an aftermarket pipe with the aftermarket intake for the jetting to work properly. But correct me if im wrong since i am not an expert at this.

No pipe and Lunch box may be hard to get tuned right. 140 may be a bit too lean. Maybe try 145. Also set air screws for that 3K idle problem.
Cool.
Srinath.

even with sputtering during downshift and some backfire u think 140 is lean? im actually considering 137.5's, what do u think?

BTW local shop wanted $275 to "clean and adjus"t the carbs