Fuel getting into oil

[Ron Hamp]

Theres been a lot of talk about the fi buikes getting fuel into the oil nd causing bearing failuers .im suprirzed that the oems dont kill the engines buy cutting the power to the fuel pump and also using some type of petcock to asure fuel does not leak by the injector while setting.

[susco64]

I've been scratching my head since day one, every time I get off my bike and don't get to turn the fuel off. Luckily, so far no issue with mine, but still check and expect that it's going to happen sooner or later. Almost makes me jump up in the middle of the night to check my oil, damn. ?

Edited March 23, 2010 by susco64

[Charlie C]

Theres been a lot of talk about the fi buikes getting fuel into the oil nd causing bearing failuers .im suprirzed that the oems dont kill the engines buy cutting the power to the fuel pump and also using some type of petcock to asure fuel does not leak by the injector while setting.

I replied to a post a few weeks back that was the same issue. Since the pressure and the power is still there from the fuel pump, there really needs to be some way to relieve the pressure. Regardless of weather there's pressure or not, the fuel should not be leaking out of the injector and into the cylinder and eventually down into the crankcase. The injector is bad if it does. 71 hrs on my kids 09 450 and no issues (knock on wood)!

Ron, I almost wonder if it's just a real cheap injector. The automobile industry has this issue also, but it's usually 10 years down the road, not 8 hours later!

[flattie]

Ron, i noticed something odd the other day when i had my bike apart. the last time i had rode it i just shut it off and didnt do anything but wash it. when i pulled the subframe/airbox i went over everything like i normally do just looking and poking around. when i opened the butterfly on the TB i noticed that the motor had stop with the intake valves open. seem to me maybe the engine is stopping in an odd postion and that if and fuel were coming out of the injector during a period of sitting that it would have a strait shot into the cylinder were it would make its way past the rings into the crankcase. i have heard that an engines typically stop in the same spot each time its shut off. could this have something to do with the fuel in oil problem? i havent had a chance to ride and retest to see if it stopped in same position.

just a thought....

[gaz_d]

I've not got a fi mx bike bike, but on cars and multi cylinder bikes they usually have a rail with a regulator valve at the end that controls the pressure. Maybe their is someway of bypassing this when you shut it down to drop the pressure and stop the injector leaking.

Maybe connecting a bypass hose to the fuel cap vent when it's not running?

[Joe_Jet]

haven't looked into the system enough to tell if it's possible, but i also suspect it may be from a fuel return or venting system problem.

my oil does smell like fuel and oil gets drippy thin after a couple rides. changing the oil more often, 1 hr vs 5.

Have not heard of a single bearing failure. be careful not to start some stupid rumor without facts to back it up. there are a few guys that have reported the fuel in oil prob and over 100 hours with no probs.

[Redrider28]

I've been scratching my head since day one, every time I get off my bike and don't get to turn the fuel off. Luckily, so far no issue with mine, but still check and expect that it's going to happen sooner or later. Almost makes me jump up in the middle of the night to check my oil, damn.?

Haha same here dude...its always on my mind ?

[Redrider28]

Theres been a lot of talk about the fi buikes getting fuel into the oil nd causing bearing failuers .im suprirzed that the oems dont kill the engines buy cutting the power to the fuel pump and also using some type of petcock to asure fuel does not leak by the injector while setting.

I've been thinking about a killswitch for the fuel pump so it can be shutdown first to allow pressure to drop before engine in shutdown

[mxjeff575]

I was talking with a friend who also owns a 10 CRF250R and had gas in his oil. He said that the owners manual says to blip the throttle 3 times before killing the engine. I wonder if revving it 3 times right before hitting the kill helps lower the line pressure. I need to read my owners manual obviously. ?

[Ron Hamp]

if some one made a kill switch that opened a circut instead of grounding it would be simple as splicing into the wiring harness @ the fuel pump .

[mrgrabow]

if some one made a kill switch that opened a circut instead of grounding it would be simple as splicing into the wiring harness @ the fuel pump .

Hmm... I used to race jet skis and used these really nice compact, handlebar mounted waterproof on/off switches (they were open-close designs, not the grounding version). Might be worth looking into...

[455]

if some one made a kill switch that opened a circut instead of grounding it would be simple as splicing into the wiring harness @ the fuel pump .

I guess if all the bikes had this fuel in the oil problem one would have to look for a fix. But the problem seems to be very sporadic. That tells me the the overall design is good from Honda; just some defective injectors or fuel contamination that causes them to leak.

So far, I have no fuel in my oil.

[waukee]

my 2010 yz has fuel in the oil, also replaced FI still having problem. I have read on TT where every brand has had at least one FI problem.

[Redrider28]

I guess if all the bikes had this fuel in the oil problem one would have to look for a fix. But the problem seems to be very sporadic. That tells me the the overall design is good from Honda; just some defective injectors or fuel contamination that causes them to leak.

So far, I have no fuel in my oil.

I'll bet there are a lot of bikes having this problem...riders are just not aware of it. My oil level doesn't rise between rides but it has a strong gas smells and its thin...even after the first fresh oil ride. The only way to be sure is to do a drop pressure test

[MRD RACING]

you could just put a small valve on the bottom of the tank and drain it and then run the fuel out of the fuel line before you park it between trips to the track , fuel injectors can become fouled very easy and drip if the fuel level is above the injector like on a bike , on cars the fuel tank is lower so they dont drip , they flow back and let air into the fuel lines and doesnt cause to much of a problem , but fouled injectors are very common , this is one of many problems FI can have , yes EFI is trick but.................

[Joe_Jet]

how hard is it to disconnect fuel pump power supply to test theory of shut down by pump to prevent fuel in oil theory?

Also, is there a return line in the sytem to return fuel supplied by the pump that exceeds demand?

[Ron Hamp]

the last time i worked on an automotive fuel injection there was a check valve before the injector set around 40#s if tthe pump was not making 50 pounds no fuel got to the injectors i dont beleive there is a check valve in the honda system .

[tech24]

You all lost me on auto FI systems. They have nothing to do with gravity and remain under pressure for hours until it slowly bleeds back into the tank through the check ball/valve in the pump or sending unit. A fuel injector should be able to hold pressure indefinently unless there is dirt in the pentile.

I don't know what to think about the bikes with a problem but sounds like a poor fuel injector design. I haven't much experience with them yet.

Is there a filter on these sysems? I assume there is. I'm am very curious on this issue.

I would imagine after the bike is shut down there is still a split second of power to the injector which may cause a little leakage but I wouldn't think it would be significant.

[Charlie C]

You all lost me on auto FI systems. They have nothing to do with gravity and remain under pressure for hours until it slowly bleeds back into the tank through the check ball/valve in the pump or sending unit. A fuel injector should be able to hold pressure indefinently unless there is dirt in the pentile.

I don't know what to think about the bikes with a problem but sounds like a poor fuel injector design. I haven't much experience with them yet.

Is there a filter on these sysems? I assume there is. I'm am very curious on this issue.

I would imagine after the bike is shut down there is still a split second of power to the injector which may cause a little leakage but I wouldn't think it would be significant.

The only filter I know of is in the tank, and it's not very good or people wouldn't be pooring their fuel through a strainer. I think you're right about the poor design. I stated above that the injectors on auto's have the same issue, but usually 7-10 years down the road and some times never, but certainly not after 5 hrs. I believe it's just a cheap injector. Someone will come up with a better design and higher quality before too much longer. They read these posts...

[whiteboy843]

I'll bet there are a lot of bikes having this problem...riders are just not aware of it. My oil level doesn't rise between rides but it has a strong gas smells and its thin...even after the first fresh oil ride. The only way to be sure is to do a drop pressure test

me too.

no rise.

but strong smell and very thin.

changing oil every ride.

its bullllshxt.

ive had a 2004 250. 2005 450. and a 2007 250.

all my bikes have been amazing with not even the smallest problem.

over $10000 in this bike and im afraid to ride it.

i would do anything to see this problem go away.