[daveyn]

Just picked up a new to me 2015 rancher and I was giving it the once over and pulled the cover on the air cleaner. There is about 1/4 inch of what appears to be very clean motor oil rolling around at the bottom of the box. I can't think of 1 single reason why somebody would do that on purpose or how the oil could get in there through some type of engine malfunction like over filling etc.
Any body out there have any thoughts or suggestions on things I might not be aware of?

 

[creed82]

My 2016 Honda Rancher showed signs of some oil getting into the airbox, I believe through the crankcase vent. I just figured if that's where it needed to go, I wouldn't worry about it. It's easy for people to mess up the oil filling process, and they may have overfilled it.

 

[daveyn]

Doing a little research on the issue and it appears to be something that happens and is not uncommon. I was pretty concerned because its at least a cup and a half of oil and the bike only has 450kilometers or about 300 miles on it . Apparently there are a number of things that could cause it such as overfilling (but I don't think the oil has ever been changed) or hard acceleration driving oil back through the breather tube or even a kink in the tube can cause it. Not going to worry about it anymore, going to drain it, do an oil change and carry on.
Thanks Creed, my initial panic has abated.

 

[retro]

Change the oil & filter (don't overfill it) and keep an eye on that airbox. When you notice the oil has darkened up change it, its saturated with carbon particles and its done. Nevermind the calendar and odometer, when its beginning to turn black get it out of there immediately... every time... and live happily ever after.

Welcome to the forums!

 

[ktriebol]

Yes, overfilling can cause oil in the airbox via the crankcase breather. One possible reason for overfilling is that the oil drain plug threads were stripped out and it was repaired in a way that partially blocks the opening for the drain, thus prohibiting all of the oil from draining out. If the usual amount of new oil is put back in, the result will be overfill. When you drain your oil, check to see if the drain threads in the crankcase have been repaired. I hope not in your case.

 

[daveyn]

ktriebol I'll check that but its not likely, when I asked the guy when the last service was done he was pretty vague about it and I took that to mean its probably never been serviced. He also doesn't look like a "change your own oil" kinda guy. the first service indicator light is on so I'm guessing the drain plug has never been pulled. I'll be doing that shortly, the bike only has 300 miles on it so I'm not overly concerned that it wasn't serviced and its also likely it wasn't overfilled, probably just abused a little out of the box.

 

[daveyn]

So cleaned out the airbox today and got 6/10 of a quart out of the airbox and it is definetly coming into the airbox through the filter as the intake after the filter had oil on the walls and the filter was soaked in what appeared to be engine oil although it did have a green tinge to it like filter oil. I also found about 3/4 inch of mud and grit in the bottom of the drain cap so I'm thinking the bike has probably been submerged, but not badly or there would have been more mud and grit in the box. I also noticed there is mud inside of the left headlight so its been in a pretty deep hole. The oil in the airbox is probably blow back although I really don't understand how that much oil could be in there, but I'm no mechanic
Knowing what I know now, is there anything else I should be checking or doing other than an oil/filter change?

 

[creed82]

So cleaned out the airbox today and got 6/10 of a quart out of the airbox and it is definetly coming into the airbox through the filter as the intake after the filter had oil on the walls and the filter was soaked in what appeared to be engine oil although it did have a green tinge to it like filter oil. I also found about 3/4 inch of mud and grit in the bottom of the drain cap so I'm thinking the bike has probably been submerged, but not badly or there would have been more mud and grit in the box. I also noticed there is mud inside of the left headlight so its been in a pretty deep hole. The oil in the airbox is probably blow back although I really don't understand how that much oil could be in there, but I'm no mechanic
Knowing what I know now, is there anything else I should be checking or doing other than an oil/filter change?

Again, I could be wrong...hope I'm not, but I'll bet if you just service it yourself, follow the Honda instructions as precisely as you can, and keep an eye on it you will not have any issues with it. Probably operator error on the part of the previous owner, or maybe the way he was running it. If it were mine I'd just get it clean and back to spec as quickly as possible, then keep an eye on it. I put 330+ hours and 3300+ miles on my 2016 Rancher and didn't have any issues with it, even though I saw some oil (not much) in the airbox.

 

[Goober]

I’ve seen oil in the airbox on two of my machines when I first got them. When the air filter and carb is really dirty and you’re putting the spurs to er I think the vacuum starts to pull oil from the crankcase.

 

[70monte]

My fiance's 2005 Rancher always has oil in the air box and inside that clear tube that is at the bottom of the air box. My 14 Rancher never has had oil in the air box yet.

 

[jdp]

I'm from a different train of thought, that tells me a problem is there, weather its Operator error or a design flaw. Drain the oil and filter change it with synthetic oil and wipe out the air box good. Run it and keep an eye on the level. It's odd you say that, all the ranchers I rode never had that issue but then again my 300 never had it either. Maybe cause I would follow Retro on post #4, hes right on the money there.

 

[TBRider]

If you roll it, the oil will drain into the airbox also.

 

[SamUK]

My boss had a very good oily coating in his Rancher airbox too when he bought it. were strict on service schedules as all our machinery and work vehicles are used daily and are always needed. Every 100 hours for anything 1000cc and under, tractors twice yearly, hand held machinery we go by visual, when the air filter needs replacing everything gets done.

After servicing at said intervals we never found any oil in the airbox, just the usual oily misting you’d expect.

Basically, treat everything mechanical as a tool, treat a tool right and it will last you for years. There’s a lot to be said for following maintenance schedules. Opinions differ though.