82 kz550 sluggish

Got an 82 kz550. I start it an let it warm up. But when I pull throttle back it revs high to 3000-6000rpm then comes back down to 1200 which is normal I think. When I give it a little throttle while riding it seems like it's dragging but if I gun it she goes full blast an dosnt seem sluggish anymore. I haven't cleaned carbs or even looked at them. I am new to this bike thing and this is my first bike. It has 7,000 miles on it. When I got it I did oil change and spark plug change. And knocked some rust off the chrome. Idk where I should start so any help would be good.

Thanks
Con

Also it's not consistent. It only does it of I let it set for like 2-3 days!

It may be dirty carbs. Before going through the effort to pull them apart and clean them you could try adding SeaFoam to a full tank of gas. Be sure to add the amount specified on the can, not the whole can. It's a bit of a long shot, but if the carbs are only a little bit dirty it may help. Also, have you used all the gas in the fuel tank and refilled yet? If the fuel is very old it could cause the bike to run poorly. Ed

When I bought it the guy filled it about 3/4 and there's about 1/4 left in it. I put seafoam in it about at 1/2 tank. I did half of what was needed to see how she would act. Should I try spraying carb cleaner in the carbs?

It wouldn't hurt. If the previous owner didn't ride it regularly the carbs may be dirty. One easy way to tell if they are really bad is to remove one carb bowl and look inside to see if you find old gasoline residue. You can do this with the carbs still one the bike. Ed

Thanks! I'll give it a try and see what I come up with!

If the fast-idle stop is set wrong, the choke will cause that hi-revving behavior of the throttle. You sometimes have to adjust it differently for summer or fall. You usually have to take the tank off to adjust it, but then you can't run it to adjust it.

Here's what I do:
home.comcast.net/~loudgpz/GPZweb/TK22mai...astIdleScrewMod.html

It won't fix the sluggish feeling, though.

Make sure it's running on all four by spraying water on the header pipes. The water should dance off each one evenly. If not, then you may have a cylinder that is not firing.

There are several manuals in my signature, and check out the valve train warning before doing anything with the valve cover.

How would do that? I need mine check, when I bought the bike, the sparks plugs were rusty, which i changed out and the oil..was black and the filter was solid hard. But now its not running, it just stopped. So I want to check my carbs.

Check your plugs again and put up pics of them. They tell a story. The good news is you have VM style carbs. No diaphragms. They should be easy to clean compared to the CV style.
BTW, I picked up a 84 LTD. Nice little bike. Six speeds? I DON'T HAVE SIX SPEEDS.
Steve