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HELP - 2001 YZ250F blowing oil at exhaust joint +more

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OK, so this issue seems to have multiple pieces that may or may not be related.

Part 1 - Couple of weeks ago bike was laid down hard on the motocross track, usual damage, grips, broken plastic, clutch lever, bent handlebar.  I was able to start it up pretty quick but was done for the day.  

Part 2 - After repairing the damage from Part 1 I decided to change oil, filled tank, checked level, all good.  Come back a few days later and the dipstick is completely dry ????  No oil on ground under bike, no drips or any obvious leaks.  So I top off the tank, no I did not measure rookie mistake I know, and leave it.  Check again a few days later, dipstick dry again.  On to Part 3

Part 3 - I try to start the bike and it will not fire for a long time, 15-20 kicks, which is unusual for this bike.  I also notice small puffs of smoke coming out of the exhaust pipe joint (not the tail piece or at the header gasket), after each kick, in the middle there is a seam on pipe near the kicker (see pic).  The bike eventually starts at which point it begins to spew significant amount of CLEAN oil out of the same joint.  We let it run for a bit but fearing an oil fire shut it down.  No smoke out the back of the bike, blue or otherwise.

Check oil dipstick, dry again?

Now bike wont start, still kicks out smoke from exhaust pipe (in the middle).  Nothing out the tail pipe, or at header.

Where did my oil go?  How is it getting into the pipe?  Clearly the oil is causing an issue, fouling plug perhaps, but I cannot imagine where it went.  

 

I would suspect rings being partially the issue but the oil mystery has me totally confused.

 

Any thoughts are greatly appreciated.

 

 

yz250f oil.png

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Well, it would appear that you have over filled it with oil. Maybe when you had the crash you got oil in the cylinder, maybe through the vent hose. Was the bike laying down or upside down for any amount of time? I'm sure you know how to properly fill and check the oil but did you run the engine for 5 min. then let it sit for another 5 min. before checking it? I'd clean the plug, start the bike and let it run until all the oil burned out of the bike. I wouldn't worry about an oil fire inside the pipe. I would how ever keep any oil dripping from the pipe wiped off. Dumping all the oil and filling it with the correct amount of oil might be a good way to start. I believe this bike calls for 1.5, 1.6 liters with a filter.

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Drain the oil completely and refill with correct amount (1.2 liters for those I think?) As mentioned run for a couple of minutes and let sit then check oil level. The oil drains into the sump when not in use and needs to be pumped back up to the frame reservoir. 

 

As for clean oil coming out the exhaust joint... that's an odd one 

Edited by Vintage Not Pimpage

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Sounds like it is overfilled.  The sump will fill up with oil when the engine is not running and oil level must be checked after letting the bike idle on level ground for a minute.  For peace of mind when you start it, shine a flashlight down the fill hole.  You'll see the oil flow.

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Thanks for all the advice.  Yes definitely over filled, did not understand the sump pump, my first Yamaha so not used to that oil in the frame situation.  Drained bike completely, changed oil filter, new plug, added EXACTLY 1.5L oil.  Kick right up, ran ok, smoked a bit as expected, but after a few laps on the track everything seemed back to normal.  Easy starting, running good.  And I learned all about Yamaha oil management.

 

THANKS TO ALL!

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