Removed old air filter and added aftermarket K&N stub air filters on my carbs. Now bike chugs to speed up.?

I've gone through this before.

Your motorcycle is no longer running because you have an incorrect fuel/air mixture being pumped into your engine.

Solution: Carburetor jetting

In a nutshell it goes like this:

Upgrade your main jet, if it feels like your bike lacks power, upgrade to the next size, if it feels like it accelerates smoothly with the right amount of power but jerks at all (don't mistake with ignition cutting) then you must downgrade to a smaller jet.

Next, You can shim the needle, this will only effect performance from about 1/4 throttle to 3/4 throttle. You can easily find a tutorial or detailed instructions on google.

Lastly, you want to adjust the pilot jet to get the smoothest idle, turning it left richens the mixture while right will lean it out. Adjust it to where it sounds the best, when it sounds good rev the engine, if it returns back to idle immediately after revving, you have a good mixture.

That rubber tube you speak of? I've been riding suzuki's all my life and there's only two tubes that I can think of. One of them is approximately 3/8" wide and is just for drainage, the other is approximately 2 1/2" wide (varies by the engine size) and feeds the air directly into the carburetor where the fuel is injected as a mist and pumped into the engine. I assume you're talking about the drainage line though, that does not connect to anything, it's just ran down to let whatever backs up into the airbox drain out the bottom of the vehicle. So that's supposed to be disconnected on the opposite side.

Aftermarket Motorcycle Air Filters

Air fuel mixture is now wrong. Need to either fix air box and put correct filter on, or adjust fuel side of mixture to get ratio back. Take it to a mechanic.

Good luck and ride safe,

Mike

Your spark plugs are the best place to check, sounds like it's running rich.

Did you plug-up that vacuum tube, if so unplug it and either find a small filter to fit the end or a way to attach it to the air-boot.

Aside from needing to re-jet for the new air cleaner , it sounds as if you've created a vacuum problem by not reconnecting that line.

You need to rejet/tune your carbs. You modified a system designed and tuned by veteran engineers. Intake and exhaust need to be properly set up . Read up on jetting for your carbs, buy a dozen or two plugs and start doing plug chops. You may end up spending a bit of time doing it, but you modified a carefully balanced system and will need to adjust and tweak it to compensate.