Want to fine-tune carbs, but not sure if they're ready

The bike ran, but it ran rough and I had never drilled the pilot screw covers when I cleaned the carbs the first time. And it's Spring which means that it was finally time to put that new (used) muffler on.

So, I got the old exhaust off, put the new exhaust on and - while I was at it - pulled the carbs, cleaned them, drilled out those little metal plugs and set the pilot screws the way it was said to. I set the float levels to - what I thought - was within spec and put the carbs back on. Bike wouldn't start. Took the carbs off, fiddled with the float levels, tried again. Now she's running, but she's running rough.

I was, perhaps, over-eager and I tried to hook a manometer (a friend of mine BOUGHT one, can you believe that?!) up to fine-tune it all.

SO... HERE'S THE PROBLEM:
I can't get a steady idle. I have to play with the throttle to get it not to stall out... then it warms up and it runs at 1500... then it will suddenly jump up to 3k rpm, then it will drop again, then act normal (1500), etc. So, it's real difficult for me to get a steady reading on this.

HERE ARE MY THOUGHTS:
It could be obvious - float levels. Pull the carbs and fiddle with those again.

It could be air-intake - there are some cracks in the rubber between engine and carbs and between carbs and airbox. They don't look like they go all the way through, but they could.

Could it be an oil change? My oil has been sitting in the bike all winter and is probably gross. Should I just try switching that sh!# up? Would that really affect the steadiness of my idle?

Any thoughts from you motorheads in cyberspace?

 

How thoroughly did you clean the carbs?

Did you take the pilot screws, their springs, tiny washers and even tinier o-rings out and clean the pilot passages? Replace the gnat's a-hole o-rings?

Did you pull the float valve seats and clean/check the beanie screeens?

How exactly did you set the float levels?

Did you bench sync the carbs before putting them back on?

What you need to do is stop "fiddling." Be methodical, careful, and thorough. Go step by step, and don't guess.

While the carbs are off is a good time to check those manifold cracks. Flex the manifolds from inside and see if the cracks go all the way through or not.

Did you have the airbox-to-carb boots back on when you were trying to sync?

 

Info: Recommended idle is ~1050 RPM

 

Hey sometimes fiddling can work. My enrichment circuit in my carbs needs some help prob but my bike was stopping at 5k rpm and I pulled the carbs and had the insane urge to ride today (first good day here in like 2 weeks) so I put it all together and it started right up. It even was trying to pull the front wheel up like it had a completely different engine in it. But were supposed to be getting rain until thursday so im contemplating pulling the tank again and removing the petcock because im thinking i may have rust in my tank=/. Im not sure how it would be the oil but I would change it anyways.manufactured oil does have a shelf life. I got a car once that when we pulled the drain plug it looked kind of like black curdled milk. I changed that oil like 3 times in a couple months to try to clean it a little