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CRANKCASE FULL OF GAS 2013 CRF450R

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I HAVE 10.2 HRS ON THIS BIKE AND THE  CRANKCASE OVERFLOWED WITH GAS. EVERY TIME I RUN THE BIKE I HAVE TO CHANGE THE OIL BECAUSE THERE IS GAS IN THE CRANKCASE. ANY ONE HAVE ANY SUGGESTIONS. I HAVE REPLACED THE INJECTOR AND IT STILL FILLS THE CRANKCASE WITH GAS. IF THE BIKE QUITS RUNNING THE CRANKCASE FILLS WITH GAS. I HAVE TALK TO SEVERAL OTHERS WHO HAVE SAME PROBLEM BUT NO SOLUTION. CAN ANY ONE HELP WITH THIS THANKS

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I've had a number of fuel injected honda's pass through my shop. Never had this problem. The only place I hear of it is this forum.

 

The reason I wonder about this is there is nothing on the bike that could power the fuel pump for a long enough time to fill the cases. Unless the bike is running. Then the fuel is burnt through the motor.

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I had a 09 that defiantly had gas going into the crank case not grant you it never overflowed but it definatly raised the level and there was no doubt it was gas from the smell I sold that heap never did figure it out

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A clogged injector (pintle stuck open) will absolutely leak fuel when the bike is shut down. The residual pressure in the fuel line pushes the fuel through the open passage that should be closed. Once residual pressure is relieved, the leaking stops. But if you start/stop your bike a bunch during an oil change you can get a lot of fuel in the oil.

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I've seen a bunch of fuel injected bikes with this problem. The first one I saw was a friends brand new at the time '09 CRF450, he had blue oil, which should have been golden brown. He was using Turbo Blue fuel and it was going into his crankcase. I just saw a guy (another friend) at a race last Sunday with a '12 KTM 350SX asking how come his oil level is going up and it smells like gas now. He asked how can this happen? He also was loosing coolant, but it wasn't obvious where it was going and that's another story.

Anyway, there is only two reasons I have ever seen that can cause this problem. One is a bad or dirty injector, leaking down each time you shut the engine off, raising the oil level a little with each shutdown.

The second is the guys that start a cold engine and constantly blip the throttle over and over again, even revving it up. This can spray too much fuel into a cold, not yet sealed combustion chamber washing past the rings. (These guys engines do not last very long, compare to bikes properly warmed up)

This is a problem, however it is not limited to one type of bike and most people know how to properly warm up a bike.

For you guys that think you must rev them up or constantly blip the throttle, stop it!

Start the bike up and let it idle for a couple minutes.

Jason

Edited by Framebreaker

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IMHO

 

Injectors WILL get stuck open if:

 

You don't filter the fuel going into your tank

You don't filter the fuel going out of your tank and into your Throttle body

You use a 'shorty' vented tank vent (they let dirt in)

You don't 'dab' the excess oil off your air filter, which will create carbon build up on the injector

You don't clean your fuel pump filter and injector nozzle (with the 9v pulsing method) every rear tire change or so

If you shut the motor off with the kill button or stall the motor without letting the bike sit and idle for at least 10 seconds first (sensors need to settle to set map)

If you start your bike and open the throttle AT ALL for the first 30 seconds. You have to let the TB sensor catch up to the surrounding atmosphere (you can do this after warm up) to set the map.

 

Ring blow-by of course is the other problem for crankase gas problems, but it starts with the fuel quality.

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From MXA regarding the '09: http://www.motocrossactionmag.com/Main/News/ASK-THE-MXPERTS-I-Have-Gasoline-In-My-2009-CRF450-4149.aspx

"Dear MXA,

I am a concerned 2009 CRF450 owner. I have read and trusted MXA's input for over 20 years. Have you had any issues on your test bikes with gas in the engine oil? Is the EFI leaking fuel into the cylinder after it is shut down? I heard of this gas causing engine damage. Can I ride my bike without fear of it blowing up?

MXA talked to Honda several times on this matter and Honda is aware of the fact that on some bikes gasoline has migrated to the crankcase (not the transmission). MXA has not had this issue on our test bikes, but yours is not the first letter we have received on the subject.

Honda says that there is no danger, as long as you drain and change your oil at regular intervals. They think the problem is caused on shut down when the fuel injector shoots (or dribbles) excess fuel into the combustion chamber. As the engine is being shut down, a small amount of gasoline makes its way past the rings and down into the crankcase. It is never enough gas to cause any trouble, but over time, the small amounts of gas can add up.

This wasn’t as much of problem on a carbureted bike as with fuel injection, but Honda doesn’t know why.

As long as you change the oil at regular intervals, the accumulation of fuel will not be a problem. Additionally, if you ride the bike very hard or very long to get it up to temperature, the gas will evaporate (although not all of it). Many riders also report a thin fluid of oil on the outside of the engine cases—this is common for riders on long trail rides (not so much motocross).

Honda did tell us that they do not recommend installing any kind of one-way valve in the gas cap vent hose.

The gas cannot cause trouble to your crank or rod as long as it doesn't exceed 15 percent of the gas/oil ratio. In summary, if you change the oil often enough to avoid it collecting in quantity, this will be a non-issue. Changing the oil is good advice for all four-stroke owners, whether they have issues with moisture or gas collecting in the bottom end or not."

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rolandk

Best information I have heard so far. Makes me feel alot better about this purchase. I was starting to think you had to have the perfect rider in a perfect world on a not so good bike. Any way I put a kill switch to the fuel pump. The engine stops in about 3-5 sec. Two kicks to restart the bike. What are your thoughts on that?

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IMHO

 

Injectors WILL get stuck open if:

 

You don't filter the fuel going into your tank

You don't filter the fuel going out of your tank and into your Throttle body

You use a 'shorty' vented tank vent (they let dirt in)

You don't 'dab' the excess oil off your air filter, which will create carbon build up on the injector

You don't clean your fuel pump filter and injector nozzle (with the 9v pulsing method) every rear tire change or so

If you shut the motor off with the kill button or stall the motor without letting the bike sit and idle for at least 10 seconds first (sensors need to settle to set map)

If you start your bike and open the throttle AT ALL for the first 30 seconds. You have to let the TB sensor catch up to the surrounding atmosphere (you can do this after warm up) to set the map.

 

Ring blow-by of course is the other problem for crankase gas problems, but it starts with the fuel quality.

Makes me want to hold onto my FCR .. even more

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Makes me want to hold onto my FCR .. even more

 

Haha once you go FI you'll never go back.

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IMHO

 

Injectors WILL get stuck open if:

 

You don't filter the fuel going into your tank

You don't filter the fuel going out of your tank and into your Throttle body.

You don't need to filter the fuel out of the tank if you use a filter sock under the cap and drain the tank properly when not in use for extended periods.

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Or put a filter in the outflow tube/neck of your fuel can. The VP jugs with the large hose used to fill the tank are great for adding a small-particle inline filter! Plus the filter slows the flow some so you don't overflow the tank...

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Honda should have adressed this problem properly 4 years ago.

A little fuel in oil is probably normal but in such amounts that it nearly flows out the oil filling hole is ridiculous.

 

Had this problem with my '10 CRF450 (after 70 Hrs) and a new injector solved it.

With my current ('12) bike same problem but began from new.

Changer injector, IAT, ECT sensors, piston/rings, warmed up extensively, covered part of radiators at low temp.

Problem is definately worse at low temps.

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for those fearing that small particles will cause an injector a problem, there is some truth to this but some of the fear is unfounded. ALL these fuel injectors have a filter basket in the top of them. The screen mesh is about 35microns. Anything smaller passes through the multi-ports of the injector anyway (these are not pintle style injectors). Anything larger will get captured in the injector's filter basket (and i would assume there is a fuel filter like on the ktm ?). j

A warning.. if you try to remove the filter basket without the proper too you will likely fail. If some of the screen falls into the injector, it is likely ruined. Do not attempt to remove the basket without the proper tool, or if you are having the injector serviced, let them do it..

 

Injectors can be diagnosed and serviced (you don't have to buy new every time). Yes, if an injector is not closing as the ecu tells it to, the residual pressure will push some fuel into the combustion chamber. I have a hard time believing "blipping" the throttle has anything to do with this. The injector does not continually fire. It is instructed to open/close based on the throttle position sensor and ecu. Will it put more gas in on an intake stroke than it needs if you open WFO at low rpm ? sure, but that will burn when the spark ignites that fuel. Ethanol can become problematic for any fuel injector (and any fuel system) when it sits for more than a couple months at a time, or if the fuel is more than a few months old.

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Being new to the 4-stokes I'm not sure if I am hijacking the thread or if its related but why does my manuel tell me to "blip" the throttle twice before hitting the kill button? What does this do? (09 CRF450)

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It's supposed to pressurize the fuel system, prepping it for the next time you start it. All of mine never really seem to need it, but most of the time I still do it.

And, if you do it with a cold engine it can cough and hesitate, which is because it is flooding the cyclinder. The excess can end up in your crankcase. Plus, revving a cold engine is just stupid.

Not a problem with a warm engine.

Jason

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I forgot to add, it's supposed to charge up the ignition too, making sure everything is ready for an easier restart.

Jason

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