I would get a set of jets from lancer and a case of ear plugs.  toss one at everyone you pass by.

No muffler...  hmmmmmm....  with very little restriction in the air path,  I would think the foillowing would be the start point and then check the color of the plug after a tank of gas.  

Low speed circuit: Pilot jet,  the 55 Lancer sent. (Air mix screw, set at idle, set to the rich side of centered between too rich and too lean)

Mid Range: if that 88 had the clips on the needle, one knotch richer. or if a white space,  1 or 2 washers.

High speed: Main Jet : 155 that Lancer sent.

The two most used things are the low speed and the mid range.    

With an open pipe you will find a little less torque at low RPM's and more "go" at higher speeds.    I opted to baffle my loud Srceaming eagle turn-out for the torque.  I commute to work and want the "get out of the way" power just in case.

so heres whats happening after the rejet.
when i start the bike i have to give it a little gas..sometimes.
it will run for a little then just shut off if i do not touch the throttle. second time starting it is harder. i have played with the idle mix screw from all the way closed to all the way open. same thing. sometimes when it dies it blows smoke out of my intake. if i ride it and stop it will soon shut off if i dont give it any throttle. what can i do?

blowing smoke out the intake on shutoff is nothing to be concerned with except for the fact that you have an '88, pre torque limiter starter gear.  It indicates that for a short bit the engine was turning backwards.

How does it start w/o choke?  you might be too rich.

How's your idle speed?  I tend to set mine high, and I seem to have less problems.

have you looked at the plug after a shut off?

I bet it's wet indicating rich

If I am running rich what jets should I switch to? I'm running the ones tmack suggested now