Riding with the choke on is a really bad idea. What it does is fouls up your plugs.

1) Your gonna have to re sync your carbs, you can get the tool for about 60 bucks

2) I think K&N would help too, better air flow to match the exhaust

 

Well I think a K&N would be worse, as it would make the bike run even MORE lean.

I think what I need to do is restrict the air that is going into the carbs.

 

you dont need to restrict the air. I have a full yoshi header and muffler, K&N filter, 1990 model carbs with bigger venturis and stock jetting. i also live at 6600 feet. if i lived closer to see level i would definately need to rejet.

i hate to sound like a broken record, but you need to sync your carbs at the very least.
you can buy the motion pro tool, or this is the one i used http://www.cbperformance.com/catalog.asp?ProductID=572 $35+shipping.

 

It's not that simple man, by blocking off your intake can not precisely equal out the air fuel ratio of this new pipe. By blocking the intake, you may actually make it run worse. Right now this new pipe is giving you the chance to improve the power output of your engine. That is the degisned purpose. Why not take advantage of this power adder and do up your carbs right to benefit from this improved performance? Re-jetting carbs is not as hard as you think.

 

clean and sync your carbs, something is clearly off i there and a good cleaning will solve a lot of things, at least you would know they are clean and could rule out a lot of things if it still acted up afterwards. are your pilots screws exposed, like have the limiter caps been removed? wonder if the previous owner messed with those

 

So Do I have to remove the carbs to sync and clean them? What is involved with "cleaning them"? I just don't want to take them apart and not be able to put them back together/get it running again...

 

yes you do. do you have a manual? you can dowload one if you dont. basically follow those instructions, it really is not that hard. any experience with carbs at all? if you can get that power out of the GTI you should be able to handle cleaning carbs lol!

 

Haha because building engines and doing turbo stuff I know, tuning cars I know, This is the only VEHICLE I have ever owned with a carb (my bike)...

 

lol, if you can figure out the rest of that stuff this should be a breeze. there is a lot of info on here as to how to do it, and a lot of people here have info and can help, myself included

 

Nice thing is that you only have to learn one carb and then repeat with the other three.
You have the skills, so just do it!