Oil in "Plenum Cover" near intakes

I'm doing the first scheduled air filter change and discovered some oil near the intakes.

So you remove the air intake tubes (air intake runner) in order to remove the air filter, which is located beneath the tank. The tubes run down to the "Plenum Cover" (has Rocket3 badge on it). With the tubes disconnected you can look inside and see the intakes. I'm seeing oil at the bottom of that cover.

My bike is one of the ones that uses oil (no visible leaks or smoke from exhaust) at the rate of about one quart every 3,000 miles.

Question: Does anyone know where the crankcase breather runs to on this bike? My guess is that it's into the Plenum cover. Otherwise, where is this oil coming from? I take it that this points to the rings not sealing well.





Has anyone else done a filter change and seen anything similar?

Further thoughts- the oil is golden and looks fairly clean. I'm running Motul 7100 which is cough syrup red. I'm now wondering if this isn't the original oil that might have come in during the initial break-in. If not from the crankcase vent tube possibly valve seals?

Where's @warp9.9 and some of the other old school guys when you need them? @TURBO200R4 ?
It seems that a recurring problem would be red or dirty red. Maybe that's an indication that I just need to clean it up and not worry about it.
Still, the mystery remains....

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I would side with you on it being old oil since its not red. I'd clean it out and keep a eye on it and the oil level. Park it a little further away from your other beast just in case its jealous
What is the pipe/hose down inside there ?

I'm thinking these bikes need a catch can if the engine vent is routed back to the intake

A buddy of mine overfill the oil his 20 up and i was behind him when he passed a bunch of hd riders . He layed fown a smoke screen from sucking oil into the engine.
Anyway i advised him to change air filter and the dealer told him it had a lot of oil in the area of the filter.
So the the blow by is going to be there untill the rings seat.
Time will tell if the rings will seat or if u have bad oil rings.

So, upon closer inspection the oil does have a slight red tinge to it- so it's not virgin, or completely virgin (well, that makes no sense in most situations, does it?) oil, afterall.

@warp9.9 turns out that pipe IS the crankcase vent. It may be somewhere in the manual, but I couldn't find anything other than a mention. Here is a mirror shot- multiple holes in the bottom of that tube designed to dump oil vapors into that space and then sucked into the intakes. Not going through the air filters, which would probably be a bad idea and clog things up quickly.

There was probably less than a teaspoon, if that, in mine but the rest of the oil it's been using is probably vaporized and going through the intakes. Most of the liquid may have been from its early days.

It seems with these new bikes that not many riders are tearing into them like the older models- either due to warranty status or just afraid to put a wrench on them. We just can't have that, so I'm jumping in when required, but I'm far from am expert. The more we can all share about the new models the better.

I just pulled the evap canister in order to get to the plugs. Remember how we all removed that on the older models? What a difference this bike is to the 2.3s where, once you've removed the stock air assembly, maintenance is a breeze.

I plan to add some updates on air and fuel filter change and plug inspection, as part of the 10k mile service sometime soon.

I was curious how the crankcase vent system worked on the new models. Looking at parts pics of the airbox I noticed there is a drain hose which I"m guessing is to route any accumulated oil from the breather vent and allow it to go back to the crankcase. Is it possible that yours is plugged or restricted??? Look at number 12 in the pic below (called Drain Stub Pipe). It doesn't show what the hose drains to but I'm guessing it wouldn't be vented to atmosphere or would it?? You can also see the pipe @warp9.9 was asking about previously, in assembly pic #9 but it doesn't look to be available separately. Can you see that drain hose on your ride??

Gregger said:

I was curious how the crankcase vent system worked on the new models. Looking at parts pics of the airbox I noticed there is a drain hose which I"m guessing is to route any accumulated oil from the breather vent and allow it to go back to the crankcase. Is it possible that yours is plugged or restricted??? Look at number 12 in the pic below (called Drain Stub Pipe). It doesn't show what the hose drains to but I'm guessing it wouldn't be vented to atmosphere or would it?? You can also see the pipe @warp9.9 was asking about previously, in assembly pic #9 but it doesn't look to be available separately. Can you see that drain hose on your ride??

Click to expand...

Gregger- thanks for your input. The long pipe in the #9 assembly is the vent pipe shown in my picture above. Unfortunately, I buttoned it all up yesterday or I could have used the mirror to have a look at the opening for #12. I could have tried to take snake it with a wire. Actually though, the amount of oil wasn't that great (maybe a teaspon) and was mostly pooled at the other end from that drain pipe, so it is probably draining well. You can see in #16 how there are "troughs" and most of the oil was at the far end- not sure of the purpose for those troughs.

Has anyone else been inside this area themselves (outside of the dealer)? @MonkeyMan - you wrote up a great DIY on removing the tank (thank you, again). Did you get into the air breather while you were there?

Looks like the L-shaped hose/formed piece is bolted to the big part of #9, the "box" part of that plenum and drains it off into the intake. What feeds the box part isn't shown here. Or where the #11 hose drains from clip #12. I'd guess both to the valve cover. Blowby vapors off top of engine (pcv) into box, condenses, and drains through L-hose into intake then gravity feeds back through #12 & #11.

Gregger said:

I was curious how the crankcase vent system worked on the new models. Looking at parts pics of the airbox I noticed there is a drain hose which I"m guessing is to route any accumulated oil from the breather vent and allow it to go back to the crankcase. Is it possible that yours is plugged or restricted??? Look at number 12 in the pic below (called Drain Stub Pipe). It doesn't show what the hose drains to but I'm guessing it wouldn't be vented to atmosphere or would it?? You can also see the pipe @warp9.9 was asking about previously, in assembly pic #9 but it doesn't look to be available separately. Can you see that drain hose on your ride??

Click to expand...

Good call
Number 12 might be a one way valve that closes when running/slight vaccum and draining with engine off.

Good morning,
This too happened to me I found this oil at my 600mi service, I inspected the air filter and found about two tablespoons of oil in the bottom of the plenum.
The dealer had over filled the oil, I’m thinking by not knowing how to check it correctly, by at least 16oz.
I’m at 5500mi now. my R3 doesn’t use any oil
I getting ready to perform my next oil change I will inspect this plenum at that time.
.