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Blow by, oil in the airbox, what's normal?


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Hi Guys, I just changed my air filter tonight at 12,400 miles for the first time. I noticed that I have oil in the front part of the airbox before the air filter. Its enough oil to coat half of the bottom of the box and enough oil to pick it up with a rag. I'd describe this as maybe a oil bottle cap full of oil but very obvious to notice.  I can also see a dark 2" circle on the old air filter showing that some of that oil was sucked into the engine. My question is, is a little oil in the airbox normal? If so, how did it get there? From poorly seated rings? Thanks for any guidance.
2001 Honda Saber - sold
2003 Yamaha FZ1 - sold
2005 Yamaha FZ6 - sold
2007 Yamaha Vstar 1300 - sold
2008 Kawasaki Versys - sold
2009 Yamaha FZ6 - sold
2010 Yamaha Raider - sold
2012 Kawasaki Ninja 1000 - sold
2014 Yamaha FJR - sold
2015 Yamaha FJ-09 - lemon back to dealer
2016 Yamaha FJ -09
 
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I have no idea how it works on an FJ 09, but all smog engines ventilate crankcase vapors through the air intake system. It may be normal, but I have not read about any other reports like yours.
 
Bad piston rings will pressurize the crank case and force more oil through the crankcase ventilation system.  But, then I would expect a lot more oil in the air filter box.
 
Do not try heavier viscosity oil. that may cause further damage to other parts of the engine.  If your engine is already worn to the point that heavier oil will help, the engine is already getting close to needing a rebuild. 
 
There may be a simple check valve in a line from crank case to air box that needs replacing.  Cheaper dino oils that tend to burn off and vaporize will leave a build up of tarnish/varnish/sludge in the PCV (positive crankcase valve, as it is called in cars), and cause it to clog up and get stuck in the open position.  The better synthetic oils tend to boil off less than the cheaper dino oils and leave less sludge behind that can clog up PCV valve, or whatever Yamaha calls it.
 
Water cooled engines tend to be able to cool themselves quite well in stop and go traffic.  I never see water temps over 204 to 2008 degrees on my bike, which I would consider normal.  So, unless your temps are getting up to 230 to 250 degrees, temperature is not part of the problem.
 
Over filling oil may be part of the problem.
 
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Ok, I will admit to originally believing an oil change took 3 quarts. I believe its really 2.7 or 2.8. So the most oil its ever had in it was 3 quarts with a filter change. So if it was overfilled it was by a tiny amount. Is that enough to matter? Also, since 3333 miles I have been using Amsoil only.
2001 Honda Saber - sold
2003 Yamaha FZ1 - sold
2005 Yamaha FZ6 - sold
2007 Yamaha Vstar 1300 - sold
2008 Kawasaki Versys - sold
2009 Yamaha FZ6 - sold
2010 Yamaha Raider - sold
2012 Kawasaki Ninja 1000 - sold
2014 Yamaha FJR - sold
2015 Yamaha FJ-09 - lemon back to dealer
2016 Yamaha FJ -09
 
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I suspect over fill with oil changes...would be nice if the aiebox has a little rubber drain valve cap like my FZ-07 has...it's big enough of a rubber cap I can fit my pinkie finger in it... I usually check it every couple weeks and find maybe a spits worth of oil collected or water if I was riding in heavy heavy rain ...
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
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Almost certainly too much oil. A very common problem with any bike with this type of sight glass - BMW boxers & TDMs being others I have owned where it is easy to overfill.
 
When you change the oil do not add all of the oil. Keep a pint/half litre back and only add this once the rest of the oil has settled, using the sight glass as a guide not a fixed number of millilitres.
 
I like to be able to see the top of the oil in the sight glass as then you know the right amount is in the sump. If the level goes over the top of the window you have no clue by how much.
This signature is left blank as the poster writes enough pretentious bollocks as it is.
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So I checked my manual. It requires 2.85 quarts with a filter change, and I have added 3 quarts on past changes. So overfilling has only been .15 quarts. Recent changes I fill via the sight glass. Hopefully that will solve any issue I may have. Thanks for all the comments.
2001 Honda Saber - sold
2003 Yamaha FZ1 - sold
2005 Yamaha FZ6 - sold
2007 Yamaha Vstar 1300 - sold
2008 Kawasaki Versys - sold
2009 Yamaha FZ6 - sold
2010 Yamaha Raider - sold
2012 Kawasaki Ninja 1000 - sold
2014 Yamaha FJR - sold
2015 Yamaha FJ-09 - lemon back to dealer
2016 Yamaha FJ -09
 
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Thanks, I wont sweat it!
2001 Honda Saber - sold
2003 Yamaha FZ1 - sold
2005 Yamaha FZ6 - sold
2007 Yamaha Vstar 1300 - sold
2008 Kawasaki Versys - sold
2009 Yamaha FZ6 - sold
2010 Yamaha Raider - sold
2012 Kawasaki Ninja 1000 - sold
2014 Yamaha FJR - sold
2015 Yamaha FJ-09 - lemon back to dealer
2016 Yamaha FJ -09
 
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BOOM!!!!!!
 
http://fj-09.org/thread/4415/sharing-failure
 
My bike had issues starting when warm etc. It was really weird but when my bike sat outside the other day uncovered when I was in school and it was 90 ish degrees outside it took me three times and some throttle to get it to stay idling. Going to remove the airbox again and see what it looks like in there. Maybe there is still some residual.
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  • 1 year later...
I bought a nice used FJ-09 from a small dealer a couple months ago. They did the oil change for me before i took delivery. I discovered it was way overfilled when it burned some oil and blue smoke came out of the exhaust. I drained off 22 oz of oil just to get it down to the high mark on the sight glass. I tore it apart to reach the airbox and found oil was pooled up in the bottom. This is my first bike with a sight glass instead of an old school dipstick. Based on my experience i would suspect it may have been slightly overfilled. 

2019 Tracer 900 GT. 2019 Yamaha XSR 900. 2002 Buell S3T Thunderbolt. 2016 FJ-09 SOLD.

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BOOM!!!!!! 
http://fj-09.org/thread/4415/sharing-failure
 
My bike had issues starting when warm etc. It was really weird but when my bike sat outside the other day uncovered when I was in school and it was 90 ish degrees outside it took me three times and some throttle to get it to stay idling. Going to remove the airbox again and see what it looks like in there. Maybe there is still some residual.
My bike is difficult to start when it sits in the hot sun for many hours, the oil levels are filled to exactly the top line on the sight glass so I know it is not overfilled, and I never use a full 3 quarts of oil. I had discussed this with the dealer a few times and after they contacted Yamaha about it, their proclamation was that this was normal. I forget the exact explanation but the heat was causing something to happen with the fuel line, probably forcing the fuel back out of the line into the tank. 
 

My air filter at 25,000km. There was some oil in the airbox, but intake ports and butterflies looked clean. Nothing unexpected. 
CROP_20171119_181346.jpg
 
IMG_20171119_151507.jpg

I just did my filter at 25K miles (Yamaha GYTR filter) and mine didn't look as bad as this. There was a super light film of oil inside of the airbox on the throttle body side, and the original filter was a few shades darker. A light coating of oil inside of the airbox is normal over time. 
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  • 3 weeks later...
BOOM!!!!!! 
http://fj-09.org/thread/4415/sharing-failure
 
My bike had issues starting when warm etc. It was really weird but when my bike sat outside the other day uncovered when I was in school and it was 90 ish degrees outside it took me three times and some throttle to get it to stay idling. Going to remove the airbox again and see what it looks like in there. Maybe there is still some residual.
My bike is difficult to start when it sits in the hot sun for many hours, the oil levels are filled to exactly the top line on the sight glass so I know it is not overfilled, and I never use a full 3 quarts of oil. I had discussed this with the dealer a few times and after they contacted Yamaha about it, their proclamation was that this was normal. I forget the exact explanation but the heat was causing something to happen with the fuel line, probably forcing the fuel back out of the line into the tank.  
 
 
 
Sorry for late reply but if you have a CA bike you need to delete the charcoal cannister. That fixed my hot start issue. Gas vapors from cannister was causign a vapor lock/rich situation
 
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  • 2 years later...

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