If the low speed jets are blocked, (as has been said they are small) and the main jets kick in when you run the bike it will rev up. It's probably also gunk in the all the usual places, float bowls, etc, incl the main fuel feed line on the carbs - not the rubber hose, the fee unit built into the carbs. I would also check the plugs and clean/replace them.Check the fuel flow by removing the main fuel line, and sucking on the vacuum hose connected on the left side of the carb bank (on 89-92 mods) could be elsewhere on others. Fuel should flow when you build up vacuum in the pipe - if not, the main filter in the tank could be blocked.
Also check the cables for jamming - not the cables themselves - the butteryfly control units. There are two cables, one pulls, one pushes. After standing that long (and having fuel in the bike) the gunk will have collected everywhere. It could be another reason for the "rev up"- the cabs may not be returning fully...............
Let us know what else you find - good luck.

 

If the throttle snaps shut then it is unlikely that it's throttle cables causing the high RPM running. The carbs are 'CV' carbs, and the slides can only open on vacuum. Step one here is to fully clean the carbs. This isn't an easy job, as idle circuits have tiny openings that are easy to clog. If you do it yourself, order up the K&L carb clean tool. It's like $6, and does a great job on the tiny jets w/o scoring up the bore, unlike a bristle from a wire brush would do (about the only other thing that fits in there).

Here is my guess: I think that the carb clean is all you need...that, and an idle speed adjustment. My guess is that the bike sat, the gas got gunky, the idle circuits got clogged, and the bike wouldn't idle. When the PO tried to run it, he discovered this, and not understanding how carbs work, he adjusted the idle up in an effort to get it to idle. It didn't work (of course) so he turned it more. Eventually he gave up, and you now have a 6000 rpm idle.

You still need to clean the carbs, but try turning the idle down a full turn, snap the throttle open/closed a few times, then start the bike, and see if the high rpm is now lower than it was before. If so, stop, clean the carbs (or get them cleaned), re-assemble, then properly set the idle speed as per the manual.

Good luck!

 

I added i can of carb cleaner to the fuel tank today. The results are as follows...

Starting her up for the first time cold with the choke on she ran ok for about 15 seconds and than the rpms started to rise as before. i can some what control the rpm with the choke leaver. once she was warm i turned the choke off but rpm would drop right away and bike turns off.
Starts no problem with out choke and i can keep her running as long as i play with the throttle. i can control the rpm around 2000 or under but as i gently give it gas and try to hold the throttle at 2200 0r more. rpms will rise on their own even with throttle held steady. have to let go to drop them and once again give it a little throttle for her not to die.
I guess its time to take the carbs apart and what a mission thats going to be as i noticed a striped screw on the carb. have to wait a couple days before I have time to tackle this mission.

I did change the spark plugs before i also took each one out today and they look good, maybe the one on cylinder 3 was little more brown.

one more question, as i mentioned that i can control the rpms at about 2000 rpms with a steady throttle. but she runs like a muscle car. i know those cars are tuned like that but why is this bike running the same way will this be also an effect of something clogged in the carb?lol.

 

Also correct me if im wrong but is the idle speed control underneath the carbs so i have to take them out before i can adjust that?

 

Nope...it's accessible on the left side...you adjust it while the bike is running (well, typically anyway). But in any case, there is no reason to run the bike until the carbs have had a full service.