I have a 2006 and recently I noticed some oil collecting around my kickstand (half dollar size). I look off the sproket cover and thought it was the shifter shaft but after further examination and someone over at ninja250.org said that it was coming from the air box. The bottom of the inside of my air box is wet with oil.

They said that the 2006 they did something different with the crank case breather or something.

Does anyone else have this problem and if so what did YOU do to fix it? Anyone have any ideas?

Just an FYI Im pretty sure I don't have to much oil in the engine because when i tip the bike up straight the eye glass shows the oil level at half to 3/4 up on the glass.

Thanks,
-Nick

When i bought mine it was over filled and did the same thing you explained after i got it home. Do a filter and oil change maybe? I havnt had a problem since

Too much backpressure in the crankcase will cause oil to come out of the intake. If it isn't overfilled make sure you get that fixed quickly or it can end in a blown seals. See if your PCV is clean and working properly. I guess it's still called a PCV valve on a bike...?

did you recently lube your chain? :)

Yes, i lube my chain every 300-500 miles. But its engine on not chain lube and it all over the INSIDE of the air box.

I have done 2 oil changes on it and it just started out of the blue.

How would I check to make sure the PVC is working?

sorry, does the pregens come with a paper filter or a foam one?

to check a pcv valve, remove it and shake it. if it rattles it's good. if not, you can try cleaning it to see if it loosens up inside. I usually use gas to clean a pcv valve.

It's a foam one, i cleaned it last oil change.

Any chance you can tell me where the PVC valve is located and maybe what it looks like.

Im still learning this bike, i mastered my KLX250 but this street bike is a little different, haha.

It's a foam one, i cleaned it last oil change.



that's most likely the problem. you over oiled the filter, the oil settled towards the bottom of the filter, dripped off and is collecting in the airbox.

does the oil in the airbox look like foam filter oil?

you have a PM.

that's most likely the problem. you over oiled the filter, the oil settled towards the bottom of the filter, dripped off and is collecting in the airbox.

does the oil in the airbox look like foam filter oil?

you have a PM.

Yup, thats what most likely happened. I had the same experience a few years back with my 05. Is the oil clean? Or is it dark? If its really dark maybe its engine oil but, if its still relatively light its from an over oiled air filter. The stock airbox has a small hole that allows moisture to drain out. It drains right in the area you are talking about. Best thing to do is pull the air filter and clean the airbox out. Then dab the air filter lightly with a paper towel to remove some of the excess oil. Im sure after you do this the leak will disappear.

No its engine oil, 100% sure. I used special red sticky filter oil for it and it was not dripping in anyway. Been working on bikes since i was 14 (now 22) and have learned not to over oil my air filters haha.

I just drained the air box and about 4oz of engine oil came out, not filter oil.

I look off the crank case hose that goes into the air box and it was fine. Blew on it and no blockage of anything, air went straight threw.

Also checked the oil sight glass (again) and it was at the half mark, right in the middle.

I know you can get a after market crank case breather, is this an option or is that only going to make the oil come out of that filter?

I am more concerned on why the oil is being shot into my air box and how I can fix it. I will look into that PVC valve next.

-Nick

No its engine oil, 100% sure. I used special red sticky filter oil for it and it was not dripping in anyway.

According to the Kawi service manual it say to use SAE 30 weight automotive oil on your air filter. Maybe the sticky filter oil is causing a problem?

I will look into it but filter oil is filter oil whether its a tacky oil designed for foam filters or motor oil. Used it in other bikes for years with no problems.

After doing some more research over at the other forum I have discovered this oil build up is normal.

When cruising at high rpm's on the highway the crank case is more pressurized and ends up pushing the oil into the air box. They recommend re-gearing and draining the air box every couple of weeks. So I will be looking into a 15t sprocket for the front.

If anyone has any fixes for this let me know.

Thanks,
-Nick

personally i don't think its normal.
i put 12k miles on my first 2006 and never once had oil in my air box. and i do almost nothing but highway driving at high rpms on stock sprockets.

haven't had that issue on my new 2006 either (1k miles so far)

i have an 07 and i have recently started to see this same issue with mine. i think its because i have only recently started riding it on the highway on my commute to work, which is only about 4 miles doing around 75mph. the first couple times it didn't happen, but now its pretty much every other time i hit the highway. i dont ever get over 9,000rpm, do you guys think that is enough to cause this pressurizing issue to cause the oil to come out of the drain tubes? i get about a 2 inch spot of oil under the bike. i have also noticed the oil that comes out is very very clean, even though my oil is about 2500 miles old.
since i have started doing the highway riding, i was going to change to a 15t front sprocket just to drop the rpm's a bit. i really have no issues with losing a bit of torque by doing so, and i figure the bike would be happier straining a bit less at highway speeds. mainly i want to keep the bike in good shap becuase my son gets his drivers license soon and i'd like to pass the bike on to him when i get my vmax in a few months. wow, while typing this i just realized how much i'll miss my lil ninja! maybe the boy will have to buy his own lol.

great forum guys, been reading for a while.
thanks for any info.

i had my bike at the shop this weekend to get new tires put on and to get a general checkup. i discussed this issue with the guys at the shop and they say they've seen it but they also note that on every single bike they've seen it on the oil had been overfilled either a lot or slightly. they said its nothing to worry about and that it'll eventually blow all the oil out over time depending on how aggressively you drive, but also noted that you could just drain you oil take out the airbox and clean the lines then put it all back together and not have that problem anymore too.

well that makes me feel better anyway, but it also kinda sucks because my dealership did the last oil change, so maybe they over filled it. as long as its not a real problem im not too worried, but maybe i'll just go ahead do my own oil change next time. thanks for the info.