Airbox leaking oil, only when parked in sun

[duckb0y]

Bike is a 2005 S2R 800 Dark. (Bought last spring)

I've noticed, both last summer and so far once this year, that my bike will leak oil from the airbox.  I know this comes from the crank case breather, but I find it odd that the only time is leaks is in my work parking lot.  The ride in to work is about 15 minutes, usually at about 7:30 or so in the morning.  Bike will get to maybe 180 degrees or thereabouts.  It will drip maybe 10 drops of very dirty oil.  The ride home obviously takes the same amount of time, however the bike has never leaked oil in my garage, so I have determined that it only leaks when parked in the sun. 

Is the breather faulty, or perhaps the reservoir under the seat is full of gunk?  The oil in the motor is always fairly clean, so I don't understand why its leaking (very!) dirty oil.  The breather itself is kind of oily on the outside, so I'm thinking it may have failed.

Has anyone else noticed that their bike has leaked a bit in the sun?

[moto]

[uclabiker06]

This probably wont help but I'll mention it just in case you have a foam filter.  My air box was leaking and I thought it was oil but I over lubricated the foam filter so it was leaking the gunk from the foam filter. JMTC

[Slide Panda]

You really aught not to have enough oil collecing in the air box that it cold leak out.  My bike's a '00 and there's only been enough to leave a tiny bit of film - which even might be oil from my air filter. 

The theory about an over oiled air filter has something to it.  But that will be very thin oil - not like motor oil.

duckboy - of your oil lever is over filled, that can lead to oil blowing out the breather.  But a goot bit would have to blow out in other to get enough into you air box to leak out as there's an oil vapor collector box between the crank case breather and your air box. 

Might need to open up the air box and see what's going on a bit...

[duckb0y]

Thanks for the replies guys.  I opened up the airbox yesterday before I made this topic to see if there was anything unusual going on.  There was a very slight trail of oil going down the side of the airbox, coming from the breather reservoir. I remember seeing this last summer too, and cleaned it up.  I also sprayed some WD-40 down the outlet hose to clean that out as well, but nothing besides clean looking WD-40 came out the other side. 

The air filter is a bone dry KN, I've never oiled it as it came with the bike that way and I don't have the kit yet.  I checked the oil level when the bike is warm, standing vertical, and running, and it is not over the high level marker, so I don't think its due to overfilling.

I just don't understand why it would do it when parked.  You would think if its gonna overflow it would do it when its running.

[Ddan]

You want to check the oil level with the bike upright  but not running. There should be little or no oil showing in the glass if the bike is running.

[Slide Panda]

The air filter is a bone dry KN, I've never oiled it as it came with the bike that way and I don't have the kit yet.  I checked the oil level when the bike is warm, standing vertical, and running, and it is not over the high level marker, so I don't think its due to overfilling.

I just don't understand why it would do it when parked.  You would think if its gonna overflow it would do it when its running.

Ok there's some problems.

1 - oil that filter pronto.  You're letting in a lot of fine dirt.  The putpose of the oil is to help trap stuff - so you're adding wear to your engine by not having the filter oiled up.

2.  The oil level is to be checked when the bike is COLD, standing vertical on level ground, and NOT running.  If you see oil between the two sight glass marks when you check it as you have described, you might well have too much oil.  And that could go a way to explaining why you're getting oil in the air box.

- it's not doing it when it's parked - you jsut notice when it's parked.  When the bikes moving, oil still might be seeping out, but the heat of the enginge might be cooking it - the speed of the air moving over it might be blowing it off, or spreading it out... etc etc. 

But when the bike's still and cooler the oil can take a more consistent path  - so more gathers which is easier to notice.

[duckb0y]

Good call yuu!  From the manual:



1. Upright
2. Warm
3. Off

I will check oil and report back.

Edit: Yep, when you check the oil like you are supposed to it is overfilled.  Gonna let some out after a while here.  I should know within a week or 2 if overfilling is the problem.  Will report back so that others can reference the thread.  Thanks to all for the help RTFM 

[Slide Panda]

Ah, I stand corrected on the warm/cold issue.  But the running/not running is really the big one - thermal expansion of engine oil isn't very much.  But with the oil pump pumping, a large volume of oil is drawn up into the heads and oil cooler.

But it looks like you're on track for a fix of your problem. 

[Howie]

It seems as of late, some owner's manuals say check cold.

[duckb0y]

I can only assume that means that the newer bikes are designed with the lines on the sight glass aligned for cold levels.  If the original manual for a certain model/year says warm, that should never change (unless there is a tech bulletin or something stating otherwise).

Edit:
Took out about .3L of oil , which when cold put the level indicator right in the middle of the 2 lines.  Let bike warm up to ~135°F, turned it off and let it sit for about 3 minutes.  Tipped it upright and the level was right at the top line. 

[duckb0y]

Rode to work on Friday, it still spat up... same amount as usual.  Did about 120 miles on Saturday and parked in the sun, nothing came out.  I think I might try cleaning the oil breather tank out this week as it is supposed to rain.

[Ddan]

You  might as well check the breather while you're at it.  It could have some crap holding it open.

[Slide Panda]

Yeah, remove that vapor collection box, and drain in.  If you had enough oil getting up those lines to leak out the air box, there's probably a good bit that's collected in that collector. 

[duckb0y]

Well, finally got around to removing the reservoir and the breather valve.  Filled the reservoir with gas, shook it around a bit, gas came out clean.  I noticed a crack next to the boss that the rectifier screws into, not sure how big of a deal that is:


The, I tackled this beast:


After I finally got it out, it looked fine.  Washed it off a bit and threw it back in.  Not sure what I'm supposed to check, but the little flappy part seemed to work fine.



Took it for about 40 minute ride, everything seems alright.  Will have to wait until I drive it to work as thats where it leaks to see if my efforts were in vain.

[teddy037.2]

man, your breather looked grubby!

it's possible that there was something faulty w/the breather, in addition to way too much oil in your bike