The oil drain ports will plug on the 125's and cause the oil to build up in the head and run out of the exhaust valve when it gets deep enough. I had one that was doing that and someone had the cylinder off at some point and got some silicone in the drain passage so it drained slow. smoked like a freight train and ran oil out of the pipe.
2000 Honda TRX450S Foreman 2" lift, 26" mud lites on ITP type 4 wheels, front disc conversion. 2002 Bombardier DS650 ron wood stage 3 kit, dual Keihin FCR39mm carbs. 1987 Yamaha 350 Big Bear 26" mud tires. 2006 Polaris 500 HO scrambler. 2001 Polaris 325 Magnum 2x4. 2004 Honda TRX90. 1986 Yamaha 125 Breeze 1996 Kawasaki KX60. 1984 Kawasaki KLT110A three wheeler. 2005 Kawasaki Vulcan 1600 Tow vehicle...2000 Dodge ram 2500 quad cab flatbed 24V Cummins 5 speed 4x4