GSXR250 exhaust upgrade

[littlegixxer]

I have a 1988 suzuki gsxr250 which i want to fit a new slip on can to,
I understand that just fitting a free flowing exhaust will seriously alter the fuelling further from ideal. It has 2 cv carbs that will have to be adjusted (hopefully not re jetted or needled), has anyone done this before?, and will the airbox replenish fast enough with a free flowing exhaust? (foam filter)
setup ideas,techniques,general know-how would be appreciated.

[geoffm]

These bikes have the 250cc version of the mighty Impulse - in fact an Impulse motor will fit fairly easily.
Trouble is the carbs are some orphan POS that you can't get jets for so rejetting is hard. You may not need to rejet.
Geoff