2003 400ex not starting help

[ProShifts17]

in the middle of riding full bore in 5th gear,it bogged down,so i shifted down into fourth and it slowly died,almost sounded like blown rings.....cranks over fine but dont start,there is NO CLICKING noises,just sounds as if the killswitch is off,its not,and it wouldnt of died like it did,SMOKE WAS POURING OUT OF DIPSTICK HOLE ON OIL TANK/COOLER???? im thinking piston and rings,anyone help please:mad:

[TheLane]

Sounds like piston and rings to me. Smoke coming out of the filler means that compression got past the rings into your bottom end.