first off, I want to apologize for being critical of most/many/some regarding wrenchables. I have other work frustrations that I seem to be taking out on you. Initiative, I just don't see it much and it irritates me. its not just wrenchables, but biz and life issues, so few actually engage but rather float. But that is not excuse for being abusive, so I am sorry and will make effort to clean it up.. it may hard for a leapord to change its spots?
I am not the only goto "mechguy" around here. plenty others to chime in. its just so quiet here. IF there was more depth or width to this particular 4m , there would be more traffic, and of course toes to step on. perhaps if there was an annual gathering of F6C motor heads, someplace central like St. Louie? not exclusive, but it might build community. I did this kind of stuff for years with the Vulcan Kawboys. we had a fistful of ner'dowells and tagalongs showing up for meet and rides and some big ditch tours..
Oil. f6ct stated one of the possible issues. excess oil will get vaporized and sent to the airbox where it is intended to get inhaled and degrade combustion. too much of this junk will coalesce and you will have liquid oil dripping all over your motor. liquid oil doesn't do well in the combustion process. EPA is the culprit for mandating this stupid design. when I get into wrenching the motor, I reroute this crankcase pressure vent line to the ground and let any (very little) oil vapors go back to planet earth from where it came. I am the king of recycle.
Ok, the real culprit in this delima is our Own Doing, our Bad Habits of constantly checking the oil to see if somehow it is 1mm low on the stick and we should ADD oil because the motor is suffering and we want to preserve this mill from any undue operating parameters (we don't have any issues with beating on it, but god forbid it should be a smidgen low on oil). So we check the oil and add more is the recipe for doing damage.
I have run multiple dozens of motors 100k's miles and watch them close. They don't consume oil. Only when running them hard 80-100mph for long distance/time aka all day , then they will blow some oil. other than that they consume zero oil. Change oil, drain and measure what comes out - all of it. you will find that it is very close to the same amount that you put in when you refill it with New oil. So where is this mysterious loss you think your seeing on the dip stick? Most /many of these new motors utilize separate cavities to hold most of the oil, but not all of it. The level of this chamber is constantly changing and your ability to read it is precarious. my advice; Don't. ride your bike. change your oil at regular intervals. measure what comes out compare to what goes in. sleep well. dam hard to shed spots. poncho