Motorcycle Repair: rough running engine, many moons, valve adjustments

Question
I own a Kawasaki 1999 1500 Drifter (Vulcan).  I beleive it is running "rough".  I sense it more through the vibrations through the floorboards, rather than hearing it through the exhaust.  Other that the spark plugs, most of the bike doesn't need adjusting.  What should I be looking for to smooth out the engine (if that's  possible).                                          My last bike (many moons ago - 1969), was a Triumph TR6C, which needed all kinds of TLC adjustments. Today's bikes seem to be "missing" all the fun stuff (valve adjustments, points, dwell, etc...).
Thanx,
Bill  

Answer
Hi Bill.
 It's not that todays bikes are missing the fun TLC stuff, it's just that they don't need it as much.

The bike could need a carb synch or timing adjustment. the average for that is about (avg) 20,000 miles. Most modern bikes are set up in such a way as to automatically reset the timing when the carbs get synchronized.  If you are past or near 50,000 miles then you do need the valves adjusted.  50,000 seems to be the majic number.  It used to be 20,000 - 25,000 miles.

Now if the bike spends time in winter or seasonal storage, then you may want to pull and clean the carbs, if it has never been done.

You will need the repair manual, so if you don't have one, then get one.  You will find it increadibly informative and useful.

Start with those.
Good luck.
FALCON