I have had lots of 2-strokes, but this think I bought for my wife from a buddy is the worst. 1 hour of riding and oil is coming out the exhaust,dripping down the silencer, onto the swingarm, down the tire,down the spokes. What a mess. Bike runs great. Tried hotter plug I run 91 oct. 40 to 1 Maxima 927 HELP!!