Does a basically stock GS500 "NEED" a jet kit to run properly after a pipe and K&N filter have been installed?

Recently bought my first bike - a used 95 GS500 with only 3,300 miles - not running but in good shape visually for $900.  It came with a V&H pipe, and I purchased a K&N filter for it.  A friend has been working on it, cleaned and synced the carbs but said it is running poorly.  Previous owner stated that he did a "re-jet" but didn't install a jet kit.  It smells to be running rich, but idles sloppy and doesn't rev smoothly.  Replaced a fauly ignition module - coils and plugs are good.  Dying to ride my bike before cold sets in - any tips on tuning the carb to get the bike running the way it should?  And if a jet kit is definitely required - what should I be looking for/what are my options?

Jet Kit = Rejetting.


If he says he rejetted, ask him what size he rejetted to.  He may of rejetted for stock set up, and now you've changed airflow characteristics of the bike, and it might require another re-jet.

It is a good idea to see what size jets are installed. The sizes are stamped on them. With a V&H and K&N...145-147.5 mains, 40 pilots (non-bleeds), 0-2 shims on the needles, and 2-3 turns on the air screw. Also, make sure there are the little o-rings are still under the vacuum ports of the slide covers.