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oil in the head???

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My buddy came over last night with his 04 crf50. He asked me if I might be able to help him fix it. He says the motor is cutting out when he has it under a heavy load and is riding it through choppy terrain. It was late and dark so I could not test the bike myself, but we decided to check a few things. The plug looked fine... a little rich but not too bad. He cleaned the filter. I decided to take a quick look at the valves. When I took off the bottom exhaust valve a bunch of oil poured out onto the floor. I would say approx 1/3 of a cup of oil. I didn't think this was normal so I looked at my CRF 50 and no oil came out of the exhaust valve on my motor. Can someone tell me if this is normal? If not, any thoughts on where the oil is coming from and how to fix it? Any advice is appreciated.

Thanks!

Pat.

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Did he happen to have the aftermarket air filter? if so, did cap off the crankcase breather tube? i would make sure that the tube is not blocked by dirt or debris.

just my 2 cents...and that comes with a guarantee...double your money back if i'm wrong.

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The bottom valve cap/cover? Oil in there would be normal. The rocker and valve are fed oil via a passage that runs along the lower cylinder stud and delivers the oil to the cam and valve stems. Maybe his was full since it was just running. Did you run your bike before you opened it? If not, maybe your bikes oil drained back into the cranckcase?

Mike

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Maybe his was full since it was just running. Did you run your bike before you opened it? If not, maybe your bikes oil drained back into the cranckcase?

Mike

you're right. No I did not run mine first. So that oil that was in his head would eventually run back down into the bottom end? His bike was sitting for about 1/2 hours before I opened the caps. Do you think that's not enough time for the oil to run back down?

thanks again.

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Sounds normal to me....the oil that is. I was just in my son's xr50 engine a few times this weekend - I did the trailbikes 88cc kit and when I opened that bottom cover, a bunch of oil spilled out...the engine was still warm.

Is your friends 50 stock? if its modded, maybe he's hitting the rev limiter? if its stock, it could be a few things. Are all of the electrical connections ok? maybe give all of the wires a once-over to rule that out.

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yeah it is stock. Thanks. I will check out wiring. Like I said I'm only going on his description of the problem since it was too late to ride it. I guess I will need to romp on it and actually hear it fail before I can begin to diagnose. We were running it on the stand in my garage and it seemed fine to me but he swears it's messed up. I'll post more after I ride it myself.

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Sounds to me like its just the float bouncing around in the carb. But the oil coming out and being in the head is perfectly normal. Heck my motor if I had a valve tappet breather would pump oil out of the head it flows so much.

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well... I test rode it over the weekend and it does exactly what my friend says it does. If you run it down the road (smooth surface) it's fine. take it through a little chop... it bogs. If you immediatly stop and let it idle, it may come back to normal, but if you continue to ride.. it dies. 10 kicks later it starts back up and runs fine. Sounds like a carb problem to me. However, I took the carb completly apart. It really seems to be operating fine. First I pulled the carb of the fuel line and opened the petcock. Gas flowed out of the tank fine... so that's not clogged. Then I pulled the bowl off the bottom of the carb and reconnected the fule line. If I move the float up gas stops coming out. If I drop the float and let it hang it pours out gas. sounds normal to me. I took the carb completly apart and all passageways seem clear. I can't really figure this out! I also ran the bike and let it idle and jiggled all electrical connections... nothing seemed to be shorting out. That was about all the time I had to work on it... but honestly I'm stumped.... I think I'm going to take the carb off my bike and put it on his and see what happens... anyone have any other thoughts?

Thanks again guys.

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Its definetly gotta be a float problem, you put your carb on it and it should run fine, then youll definetly know.

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