Motorcycle Repair: FUEL AND OIL OVERFLOWING, cumbustion, filter area

Question
FALCON, HERE IS MY PROBLEM, MY 1983 YAMAHA MIDNIGHT MAXIM 750 4CYL. HAD BEEN SITTING FOR ABOUT 14 MONTHS. WHEN I WENT TO START IT AFTER PUTTING IN FRESH GASOLINE AND CHARGING THE BATTERY,I CHOKED THE ENGINE AND ATTEMPTED TO START IT AFTER A FEW TRIES IT BARELY CRANKED OVER BUT IT RAN FOR ABOUT 45 SECONDS THEN DIED OUT AMID A CLOUD OF BLUE-BLACK SMOKE LOOKING DOWN I SAW A LARGE PUDDLE OF GAS/OIL FORMING. TRACING THE LEAK TO THE AIR FILTER AREA YET NOT KNOWING HOW THAT COULD BE HAPPENING. MY QUESTION IS WHAT WOULD CAUSE THIS AND HOW DO I FIX IT? ALSO CAN IT BE FIXED BY A MECANICALLY CHALLENGED PERSON LIKE MYSELF?

Answer
Hi Tank.
 Part of the problem is the bike sat for 14 months.  You will need to pull, disassemble and clean the carbs as well as probably doing a reseal on the tank to seal out the varnish that has built up inside.

Also, you will want to check the airbox for anything that may have built up in there (like critters that may have nested).  Check the air filter as well.  If it's dirty, replace it.

Check the valves, timing and gap.  The repair manual will have the specs on everything on the bike.

I had the same problem on my XJ750M and changing the air filter fixed it.  But the blue smoke is indicative of oil intrusion into the cylinder during cumbustion.  There will usually be a very small amount of that, but you shouldn't be burning oil enough to change the color of the exhaust as you have described.

Start with those and let me know how it goes.
Good luck.
FALCON