I am **** about warming up my engines so I doubt that pertains to my situation, but that does make some sense being a dry sump engine. Like I said, mine use to do it all the time and now has mysteriously quit........

Another issue about the overoiling the filter theory comes to mind. I oil all my filters the same on all my quads, so why don't all of them have oil in the airbox and not just the Rancher if that's the problem??? It just doesn't make sense in my case.

Actually as I recall, I have had oil occasionally in the airbox of the Recon and 250EX, so I think it has more to do with the location of the breather (external on the outside of the air filter), than anything else???? The higher end Honda sport quads have their breathers attached directly to the air intake boot between the airbox and the carburator, so if you were sucking oil on one of those you are less likely to notice it.

 

I still have 2 400ex quads and had 1 other. I've had crud in the bottom of the filter from all of them. When I used blue filter oil, it was blue. When I switched to Amsoil, it is now clear or black depending on how long I wait to clean it up. I've had oil drip down from the filter and fill the clear thingee before I've even road. I don't think anyone said this is the one cause. I agree with all the posts. It could be this, it could be that. Check them all out and see what your situation might be. I am willing to bet my house that mine is from the oil filter...

/Jon

 

Sounds like you may have had the oil level a bit high.
Just keep an eye on it and only check it after you warm it up. The Honda dry sump system is prone to "flowback", so the oil level MAY appear to be low if the engine has sat for any length of time.