I am stumped. This Baja 50 is a 2005 but it is brand new, it has never been used. Installed new battery, cleaned carb, replaced key switch(lost key), and as expected it fired up. Ran it at idle for about 45 seconds and suddenly it spuged a puddle of oil from vent tube on crank case. Not a splash, but a quart. Shut it down checked oil level. Full to bottom of threads. Figured it was overfilled. Started it again and after a minute.... out came the oil. HELP I have never seen this before. Any suggestions,

Note: no smoke coming from exhaust.... no oil from carb