Motorcycle Repair: 1996 yamaha xt350, yamaha xt350, rare problems

Question
I have a 1996 yamaha  xt350 single cylinder 4 stroke dual sport bike.  I just bought it, and it has 5500 miles and the previous owner had ridden it much in the past year or so.  I rode it home about 30 miles and about 20 miles today to and from work.  I was coming home and gunned it in first gear and than closed the the throttle quickly.   The bike backfired and popped, then died out.  I walked it home, and attempted to restart.  It would fire up and run for about 5 seconds before dieing out.  Could a lack of valve adjustments have caused something to jump loose or jump time or could it have flooded?

Answer
Hi Rick,

My first thoughts would be to check the normal things you would
check when doing a tune up.

Is the fuel tank full?
Is the fuel valve set on reserve or "on".
Spark plug look okay?
Air filter okay?
Engine stop/run switch on?

Drain the carb, see if fuel is getting to it.
Maybe the float got stuck closed.

Check compression. This will verify
if the valve clearance is okay and possibly
the valve timing as well.

If the spark to the plug looks good then try some
carb spray or a quick spray of starting fluid
in the back of the carb to see if it runs on that.

It might be a lack of fuel to the carb, a dirty carb or maybe the
carb is sucking air around the mounting rubber.

One backfire should't really hurt anything but
can be a result of lacking fuel for some reason.

A bad spark plug or cap can also stop the engine.

Look for the simple things first before assuming a
timing chain jump or whatever. Those are very rare
problems. Let me know if you notice anything else.

Wayne S.