Motorcycle Repair: 1994 yamaha virago 750, yamaha virago 750, center electrode

Question
The spark plugs on my 1994 yamaha virago 750 keep filing out. I have rebuilt the carbs . Made sure I installed the right jets and it is still filing out the plugs. Please let me know what else I can do to fix this problem. Thanks

Answer
Gary,

is this oil fouling or fuel fouling?
If it's oil the engine may need a rebuild.
If it's fuel, you could try lowering the
carb needles. Also some of the ngk
plugs have a small center electrode
which resists fouling.
If your spark plugs are black you may
be able to go one heat range hotter
on your plugs, but be careful because
of the added heat.
Is your air filter clear?
Check that choke is not on partially.