I just got my son a '98 KX60. I'm running Rock Oil K2 Plus at 32:1 like it says on the fender. It smokes and doesn't run too clean in the lower and mid range.
What mix ratios are safe? I'm pretty sure I can run it 40:1 or more, but I'm conservative now.
I'm at sea level. Has anyone gone leaner than stock on the pilot jet? Also, I figure I'll lower the needel (raise the clip), once I choose a mix ratio.
Stick to 32:1 as 40:1 will actuall allow more fuel into the mix because of less oil in the same volume.
Rock oil I have not tested or used. Some oils spooge alot and seem dirty at partial throttle because the bike does not generate enough heat to vaporize the dilutant in the oil (that leaves the actual oil fall into the crankcase and not out the exhaust).
Careful jetting should help alot along with good fuel.
I run 40:1 with no problem in the KX65. key being using a good quality synthetic premix...not sure what rock k2 oil is. We use motorex cross power 2T. But smoking could be right side crank seal leaking too. Also if you are too rich fuel/air mixture. Whether you choose 16:1 or 40:1 the key is you actual jetting setup. Like Toby said too where you guy sits in the revs depends too. If you jet for topend but the revs never reach them then you'll always have problems.
How can you tell if the seal needs replacing? This bike is 5 years old, but it's been ridden very little (the original rear tire is still good).
Should I replace it just for good measure, or tweak the jetting first? This bike does run good in the high end, but it hits the power band hard, like it is lacking in low end.
-Toby