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Overflow coming out the oil check in frame?


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Just bought another used 03 YZ250f for $900 (I have another one that I redid over the winter for my personal bike - I plan to resell this one). Bike looks good for the year.

http://i175.photobucket.com/albums/w134/robwbright/100_2107.jpg

http://i175.photobucket.com/albums/w134/robwbright/100_2108.jpg

It runs and idles well. Generally in good shape. According to the seller, it hasn't been ridden much ("not even a tank full - I have a 450 that I race and I just haven't ridden this one much") in the last year since a total engine rebuild including crank, rod, piston, valves, etc. . . It does appear to have had recent motor work done judging from how clean it is and how the gaskets look. When I bought it, there appeared to be oil on the oil check stick.

Anyway, I brought it home and started checking everything. Added coolant and started it up for about 2 minutes. Shut it off and pulled the oil check stick in the upper part of the frame.

To my surprise, fluid started spewing out of the oil check hole. I immediately thought it might be coolant in the oil. However, it was a bit strange, as the coolant level appeared to be staying the same.

I drained the coolant and it did not appear to have oil in it - at least not much.

I drained the oil and it was VERY thin - like a zero weight oil - almost like water. Brown. I couldn't really tell whether it had coolant in it or not - I wouldn't really describe it as milky.

Just to test things out, I refilled with one quart of new oil and of coolant. Started it up and it immediately began spewing fluid out of the oil check hole. Spewed quite a bit - took several shop towels to clean up.

Emptied the coolant and it looked just like it did when I put it in.

I began draining the oil and only got about 1/4 to 1/3 of a quart out of the oil drain. It was dirtier than when I put it in and seemed thinner.

I have to assume its coolant in the oil unless someone else has a better idea.

Diagnosis?

Leaky water pump seal? Leaky head gasket and/or warped head?

Any help would be greatly appreciated.

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After some more research, it occurred to me that it could be gas in the oil. Dunno how that could be, but just a thought.

It was odd that as I was loading up the bike to bring it home I was just going to lay it in the bed of the truck instead of tying it down. The petcock was off and gas poured and poured out the overflow - much more than I would think would be in the float.

We finally picked it up and tied it down. Dunno if that has anything to do with the oil related problem, but it was odd.

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Your float is stuck or your carb is on crooked.

Is that an answer to both questions or just to the gas continuing to pour out of the overflow from the carb?

And how would gas get to the float if the petcock is off? It leaked A LOT of gas laying in the back of the truck.

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Also, Are you sure you dont have too much oil in the bike. I would empty the oil from the tank bolt in the frame (clean off the screen while your there), open the drain plug on the motor, get all oil out and put in just one quart of oil. Your capacity should be 1.1-1.2 quarts of oil.

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what type of oil are you using ? does the oil have a strong gas smell ?

coolant and synthetic oil do not look milky when mixed.

It is hard to see coolant mixed with a synthetic oil .

as for the oil blowing out sounds like blow by to me ...rings.

i am not a motorcycle mechanic just personal experience.

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I have actually had this happen to me on a '06 WR450f and it was caused by brain fade. This was right after I had changed the oil. I had rushed through it and thought I did it right. I ended up using a fork oil remover to suck oil out of the frame check tube to get it to stop.

As I was doing this I looked at the frame a little closer and then it hit me: I had forgotten to drain the frame when I changed the oil. The oil that was coming out of the dipstick hole was the oil that was in the frame being displaced by the oil I had just put in the engine.

Needless to say, once I drained the frame by removing the bolt right where the frame splits apart the problem went away. I then just topped it off once the oil warmed up.

One great thing about the aluminum frame on my '08 WR250f is that the oil isn't in the frame any more.

Good luck!!

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what type of oil are you using ? does the oil have a strong gas smell ?

coolant and synthetic oil do not look milky when mixed.

It is hard to see coolant mixed with a synthetic oil .

as for the oil blowing out sounds like blow by to me ...rings.

i am not a motorcycle mechanic just personal experience.

Dunno what kind of oil was in it when I bought it.

I used synthetic when I put new in.

If it's rings, then the seller lied about the engine work - and he didn't lie about anything else I've noted yet - and he did disclose other issues with the bike.

We'll see, I guess.

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I have actually had this happen to me on a '06 WR450f and it was caused by brain fade. This was right after I had changed the oil. I had rushed through it and thought I did it right. I ended up using a fork oil remover to suck oil out of the frame check tube to get it to stop.

As I was doing this I looked at the frame a little closer and then it hit me: I had forgotten to drain the frame when I changed the oil. The oil that was coming out of the dipstick hole was the oil that was in the frame being displaced by the oil I had just put in the engine.

Needless to say, once I drained the frame by removing the bolt right where the frame splits apart the problem went away. I then just topped it off once the oil warmed up.

One great thing about the aluminum frame on my '08 WR250f is that the oil isn't in the frame any more.

Good luck!!

That may well be the resolution. I didn't drain the frame oil.

That will be a BIG relief if it fixes the problem.

It does not seem to explain why the oil was so thin at first - but I suppose there are any number of reasons that could be.

I'll check it out.

Thanks a lot.

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As mentioned above you might have too much oil in the motor....Generally I like to start the motor and let it pump the sump out back into the frame before checking the oil level.......Does the oil smell like gasoline? When you have a problem like that the oil is very thin (as mentioned) and smells like Gas) The float valve would have to be really bad and the bike set for a long time with the petcock on to get that much gas in the crankcase.....and it would be running out on the floor from the over flow hose on the carb...

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As mentioned above you might have too much oil in the motor....Generally I like to start the motor and let it pump the sump out back into the frame before checking the oil level.......Does the oil smell like gasoline? When you have a problem like that the oil is very thin (as mentioned) and smells like Gas) The float valve would have to be really bad and the bike set for a long time with the petcock on to get that much gas in the crankcase.....and it would be running out on the floor from the over flow hose on the carb...

There was too much oil - drained ALL of it and started from scratch. It does smell like gas.

The petcock is not closing completely and I just discovered that the vent tube coming off the bottom of the carb has a SCREW stuk up in it. Weird.

The bike started and ran fine. No spewing oil out of the oil check in the frame. No noticible change in the coolant level.

Shut it down and pulled the carb to clean and check the float, etc. . .

Thanks

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There was too much oil - drained ALL of it and started from scratch. It does smell like gas.

The petcock is not closing completely and I just discovered that the vent tube coming off the bottom of the carb has a SCREW stuk up in it. Weird.

The bike started and ran fine. No spewing oil out of the oil check in the frame. No noticible change in the coolant level.

Shut it down and pulled the carb to clean and check the float, etc. . .

Thanks

The screw was put in there probably because the float is faulty AND so is the fuel petcock.

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