Motorcycle Repair: 1989 yamaha, valve timing, fuel filter

Question
my 1989 yamaha will start and go about 2 miles before it quits, have changed plugs and air filter, what else could it be?and drained gas put more in still backfires once i awhile  

Answer
Hi Charlotte.

Check your fuel filter and your air filter.  It may be clogged or excessively dirty.  Also make sure that the valve timing and gap is correct.

 Is the bike due or over due for that? refer to your repair manual for the specs and schedule.

Let me know what you find.
Good luck and ride safe.
FALCON