All these suggestions are great. You people are experts or something
Oaklandish: If you want this sucker to run right, right off the bat, my advice is a good thorough carb cleaning. Get yourself a manual if you want to do it right.
1.) Take the carbs out
2.) Take the carbs apart, making SPECIAL note how many turns the air/fuel mixture screw is turned in. The way I do it, is mark with a screw driver on the outside of where the air/fuel mixture screw lines up, then count in 1/2 turns as you turn it all the way to the bottom. It should be right around 2.5, but I might be off. Be as exact as you can. See if both carbs mach
3.) Take everything else apart.
4.) Use some nasty carb cleaner on all the metal parts and scrub 'em clean. If it's metal, blast it clean with compressed air. If it's plastic, or the thin rubber on your slides, be very careful, and use a less harsh chemical cleaner... You can also get away with cleaning everything with gas.
WARNING: This isn't for the hasty, or the brutish. Use a light, careful touch, take your time, have a beer, and make sure you DO NOT mess up your slides, needle or jets...
5.) Put everything back together once the ether has evaporated off, and you're sure it's not going to eat your rubber seals. Make sure your air/fuel screws are set at the same point as when you took them out.
6.) Clean all the lines with not-so-harsh chemicals. Gas and compressed air should work fine for this. Keep in mind, you don't need to worry about vacuum lines, they don't carry gas and gunk...
7.) Take off the petcock from your gas tank, clean it with not-so-nasty chemicals, submerge it in gas, and don't use 80psi or more to blow it out.
8.) Rinse your gas tank with gas for like 30 minutes to make sure you get all the bad gas out...
9.) Put everything back on the bike as you took it off, fill 'er with gas, turn the petcock to PRI, and fire her up... It will work like a charm.
The reason your bike almost dies with throttle, and the idle is sporadic is because you're running rich, very. Thus, if fuel is flowing, and you take the idle off, she'll be able to purr like the wonderful beast she is.
While you're at it, give the bike a good look see for these things:
Oil - could probably use a change, due to being old, unused.
Airfilter- clean and oiled?
Chain - rusty, well lubed?
That should get you on the road. Post with more problems.
You could also go the lazy route, throw A LOT of seafoam in your tank, and just let it idle through a tank of gas or something. I know of people who've done that, but I'm too much of a control freak to do so myself. I want to my reflection in my carb bodies, and know, when I twist that throttle, it will be a beautiful sound, and not some frustration BS...
Let your story be a warning for all those who think it isn't necessary to "winterize" a bike - I just ride her year round
good luck, and let us know what's up. Welcome to the board by the way!