2010 yz450 gas in oil


42 replies to this topic
  • rickallen124

Posted January 17, 2010 - 03:09 PM

#21

Didn't honda have some sort of bulletin about this? If I remember correctly honda recommended that you didn't blip the throttle while the bike was warming up and that you put the motor at tdc so that all of the valves where closed while the bike was sitting.

  • The Captain

Posted January 17, 2010 - 03:22 PM

#22

Didn't honda have some sort of bulletin about this?


Not that I recall. It is an extremely isolated situation with the 09's. Sure a few on TT have mentioned they've had the problem, but it's probably .02% of all 09's out there. You also must understand some that are reporting the problem where checking the oil improperly. Not all, but some. FWIW, I know of 8 09 450r's locally and not one had a problem with gas in the oil. In my series there are probably 20 guys or so running the bike and none of them have reported gas in the oil either.

  • rickallen124

Posted January 17, 2010 - 04:20 PM

#23

Maybe it wasn't an official bulletin. I think it was MXAs response to the question about fuel in the oil.

  • Greg_T_M

Posted January 17, 2010 - 04:36 PM

#24

Purely speculation but my guess is that the gas in the oil is coming from not being burned in the combustion chamber. This can be caused from lugging the motor too much and/or running rich. I would think, unless there is some type of mechanical failure in the injector, fuel would not be able to pass without pressure from the fuel pump while not running.

  • SNO-PRO

Posted January 18, 2010 - 05:12 AM

#25

"Waukee" what kind of ambient(outside air) tempature are you running in? I have found through Grayracers help my bike is not running warm enough thus causing fuel in my oil.

  • ProMed

Posted January 18, 2010 - 07:00 AM

#26

my bike is not running warm enough thus causing fuel in my oil.

Can you explain this one a little more??

  • waukee

Posted January 18, 2010 - 07:07 AM

#27

it was around 55 degrees

  • SNO-PRO

Posted January 18, 2010 - 07:26 AM

#28

"waukee" I did not see a problem with mine in dirt at 55 degrees. Do you have the tuner for it? If so whats your water tempature when riding?

"ProMed" read the post "2010 450 cold weather" to explain it better: (Link) http://www.thumperta...ad.php?t=865788

  • mdkcrf250r

Posted January 19, 2010 - 05:04 AM

#29

Unless the volume of oil in the case is increasing you do not have a problem. The smell of gas in oil is not anything to be concerned about.


Exactly. Most manufactures require changing the oil before doing an exhaust gas analyzer test as the gas in the oil will naturally get past the rings and show excessive hydrocarbons on the test....Gas in the oil is inevitable..An amount to change the level of oil and you got problems.

  • ProMed

Posted January 19, 2010 - 04:08 PM

#30

How hard of a job is it to change out an injector?

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  • waukee

Posted March 09, 2010 - 10:03 AM

#31

changed the injector still gas in the oil, is anybody having this problem, I know the Honda guys are

  • grayracer513

Posted March 09, 2010 - 10:11 AM

#32

The problem will probably disappear with either warmer weather, or with completely warming up the engine. When you flip the choke off with a carb, it runs in the warm engine mode until it gets hot enough to run correctly, being too lean in the meantime. When you push the cold start plunger closed on an EFI, the system compensates for lower coolant temps with extra fuel, which makes it run better, but can lead to contaminated oil in the cold. Read this thread through. One owner decided to block the radiators to boost coolant temps to a normal level:

http://www.thumperta...833#post9052833

  • Drew778

Posted June 21, 2010 - 11:24 PM

#33

I also smell gas in my oil and on my oil filter when I change oil, I tried opening the filler cap after 5 hours of ride time and I did not smell any gas.

The oil is still pretty clean when I change it, wouldn't the oil turn black it a lot fuel was getting in?

I just plan on changing oil more often just to be safe!

  • poliisi2

Posted June 22, 2010 - 07:05 AM

#34

FI can be too rich did you ride in cold weather? Suzuki 250 2010 have same problem its because FI is too rich.

  • gruberyz

Posted June 22, 2010 - 07:11 AM

#35

Do the fuel pumps hold pressure after you shut off the motor? Seems this could lead to fuel passing into cylnder or do they bypass unused fuel like an automotive FI system? Constant vane rotary pumps need to bypass fuel to keep system cool and lubed

  • grayracer513

Posted June 22, 2010 - 07:43 AM

#36

Bypass circulation and maintaining fuel pressure after shutoff are two different things. GM and most Aisin/Bosch fuel injection systems do both. They circulate fuel using feed and return hoses, but when shut down, the fuel pressure stays up in the fuel rail. This is done to reduce cranking time when starting. Jeep 4.0L engines of the '90's allowed fuel pressure to drop to zero, and the fuel pump only ran while cranking or while the engine actually ran, and were notorious for long cranking times necessary to get the pressure back up to operating levels.

  • whiskey wheelie

Posted June 22, 2010 - 10:00 AM

#37

The problem will probably disappear with either warmer weather, or with completely warming up the engine. When you flip the choke off with a carb, it runs in the warm engine mode until it gets hot enough to run correctly, being too lean in the meantime. When you push the cold start plunger closed on an EFI, the system compensates for lower coolant temps with extra fuel, which makes it run better, but can lead to contaminated oil in the cold. Read this thread through. One owner decided to block the radiators to boost coolant temps to a normal level:

http://www.thumperta...833#post9052833


After talking to my buddy who is the yamaha tech for n. ca. he told me that you need to make sure your running an oil that provides good start up protection like a 10-50. He also did tell me the same thing that you need to make sure it warms up for 2-3 minutes before riding because of oil hitting the cold piston and cylinder and something to do wtih higher pressure which causes gas to pass the rings with different combustion or something? I thought this same issue with pressure also had something to do with the head gasket seal if I remember right and the issues the 2010s have been having.

  • LT785

Posted January 15, 2012 - 05:52 PM

#38

I have a 2010 yz 450 and my friend ken has a 2011. We have been riding in 24 to 45 degree weather the past couple weeks because the alternative is not riding at all. We put 5 hours in 2 seperate rides on a mx track in the NW, and noticed that the oil was looking thin and the oil level looked high. Ken noticed his new 11 with 24 hours on it smelled gassy and high level. I checked mine today. I normally put in 33 oz of delo 15-40 every 5 hours, I normally drain 2 drains on the engine. One is a 12 mm in front of the clutch cover on the bottom and side of the engine and the other is the obvious oil drain on the bottom in the rear of the engine. I found that there were 10 oz of extra fluid in it when I changed it. It was very thin and smelled of gas. I run the mxa "less hit map" with -1 more on the values that deviate from stock and -1 on the values that are more than -3 from the field next to it in the FI. I warm my bike up for about 10 mins in cold weather before I ride.

I have read through all the posts on this topic and have found some great info. Thanks to all for the input. It sounds like cold weather is messing with fluid temp sensor and causing an abundance of fuel to be introduced into the system. First I will see what the operating temp is with the tuner. If less than 160 I will try taping up the radiators completely to get some temp in the fluids.

My question is this. Is it Fi system allowing fuel to pass by when the engine is off? Is it pumping extra fuel in upon warm up due to cold fluid temps? Or Is it pumping extra fuel when the throttle is opened at normal temps? It seems to run like normal and I am confused at how that could be if my problems are a result while the engine is running. My experience with engines tells me that extra fuel at any rpm causes the engine to run poorly. Blubbery rich right? If there is raw fuel in on the rings and piston would'nt it run rich?
Just trying to figure it out. If you have an FI yz 450 and you are riding in freezing temps check the amount of oil you drain out and see. We are 2 for 2 on this issue.
Thanks

Edited by LT785, January 15, 2012 - 10:21 PM.


  • grayracer513

Posted January 15, 2012 - 09:03 PM

#39

My question is this. Is it Fi system allowing fuel to pass by when the engine is off? Is it pumping extra fuel in upon warm up due to cold fluid temps? Or Is it pumping extra fuel at when the throttle is opened at normal temps? It seems to run like normal and I am confused at how that could be if my problems are a result while the engine is running. My experience with engines tells me that extra fuel at any rpm causes the engine to run poorly. Blubbery rich right? If there is raw fuel in on the rings and piston would'nt it run rich?

If the fuel were to get into the combustion process, yes, but remember that the crankcase and combustion chamber in a four stroke are sealed apart from one another, so it's very difficult for oil, even if contaminated with gas, to get into the top end from the crankcase. When an engine is cold, it needs an excess of fuel to cause enough of it to be vaporized when the spark goes off for the engine to run at all. As Air/fuel enters the engine, fuel condenses out of the air charge as it comes in contact with colder than normal metal surfaces. Some of the excess liquid fuel is forced past the rings into the crankcase before it's exposed to flame. Getting the engine up to temp is apparently the fix for it.

  • rdefonce

Posted January 16, 2012 - 10:25 AM

#40

hay there, I have just stumbled across your thread and find it quite interesting, I have just done an oil change on my 05 rmz 450 and have found the same problem except my oil level has gone from 1500mls to 2000mls in 5 hrs riding. What I have learnt so far is it is either the rings have gone or that if you whick the throttle before the engine is warm it lets fuel by the rings. I realise we have completely different bikes and I don't have EFI but find it interesting that we have similar issues


That makes sense that it's rings or incorrect warm-up. Even though an injector nozzle was slightly weeping, wouldn't that fuel just go into the combustion chamber? (How would it get into the oil system, since it's totally separate system.)





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