Motorcycle Repair: KX 85, dirty oil, premix

Question
I have just bought a 2002 KX 85 for my son and it seem that when he rides it with out riding it hard, it sometimes tries to bog down when he takes off, it also seems to smoke a little more than it should when I ride it, and get on it pretty hard. There is also some oil in present at the end of the muffler after riding it, is this normal, this is my first two-stroke. Thanks Mark

Answer
Hi Mark, yep thats absolutely normal for a little KX with a possibly plugged air filter and possibly too rich on the premix and or poor quality premix. Check the air filter very carefully, clean it and oil it. Use only quality premix like Dumond Tech for example. Mix your fuel a little leaner, not too much though we dont want to burn a hole in the piston or blow the ring. If your mixing 50:1 thats probably too rich, drop down to 40:1 and for god sakes use a Ratio Rite to mix with, dont guess. If your already running your premix relatively lean and the filters ok then it may be time to repack the silencer if it has one or upgrade to a silencer that flows better. It smokes when you ride it hard because you are too darn big for it, stay off of it or it will seize. The oil at the end of the muffler is normal, two strokes are dirty, oil burning smokey and loud but they sure do tear it up. have fun and I hope this helped

Randy