Urgent help for XL250 - fuel in oil????

[MX?]

Anyone help with this?
Out of the blue the old girl seems to be running very rich....blowing a fair bit of black smoke. Also the oil appears diluted as though there is fuel in it?? getting some dripping from the crankcase breather as well.
Bike starts OK, though when changing the plug it looked like a small piece of metal on it??
Previously it had been flooding a bit from the carb overflow, so I've had the float bowl off and pulled the floats and needle out...put it all back together and it seems that part of the problem is cured.
I'll change the oil and see what happens I guess..any thoughs

[sudman]

If it's over rich you get bore washing & fuel will go down passed the rings & mix with the oil, but metal on the plug does not sound good.

[lc4]

Replace the needle and seat.

[MX?]

Well I've jiggled the needle and seat around and shut off the float level slightly earlier and it doesn't seem to be overflowing now. Changed the oil, sploshed out everywhere, might as well have been full of kero to look at the consistency of the oil???
Guess I see how it goes at the meet tomorrow.

[paul]

broken ring /

[GMC]

Some ride-on mowers suffer from this.
If the fuel is not turned off then when it sits around for any time and the needle & seat are a bit dodgy then the fuel can fill the carby, run down the inlet tract and into the motor where it will easily slip past the rings of a cold engine.
It's a certain set of circumstance's that let this happen but there is not necessarily something wrong with the bike except a dodgy needle & seat and / or a fuel tap that doesn't shut off properly.

Check the fuel tap does seal and make sure it’s turned off between events

[MX?]

Thanks for the replies!
Well I changed the oil etc. took it to the meet on Sunday and it ran faultlessly (Unlike it's rider)
Seems that yes, it was just one of those things 
Certainly ended up with a ton of petrol in the sump....have never seen that before and was expecting something expensive as the outcome.
I'll replace the needle and seat though just to make sure.

[dave]

Sounds like you were riding a ticking fuel bomb around. BOOM! and metal fag's everywhere.......legs, arse, crouch among other places  :'(

[MX?]

That thought did cross my mind afterwards.

[Dave D]

Yep it sounds like there was some muck in the needle & seat, I would also sugest a clean out of your tank.

This is also a common problem on old harley motors that ran bendix carbs.....