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2 stroke dirt bike question (yz250)

Discussion in 'Technical and Troubleshooting Torque' started by avanti_rider, Aug 2, 2010.

  1. Hi guys, Had a bit of a search on the forum but can't find exactly what i'm looking for.

    I am looking at buying an 08 YZ250 with about 10hrs on it. When i went to have a look at it tonight, we started it up and all sounded and run well, then i turned it off and wheeled it back into the garage and while i was negotiating with the owner, i noticed black oil leaking out the (crankcase?) breather tube.

    Is this a normal occurrence? The guy said the gearbox oil had been changed not long ago and it would have had ~10 minutes use after. Is it possible it is just spewing out excess gearbox oil?

    Cheers Guys
  2. It is possible for there to be a small amount of oil leaked from the breather tube. The bike as a whole holds about 750is ml of oil most of that is in the tranny, as it heats up the oil expands, if it is a little over full some will escape out the breather tube. it shouldn't be a problem at all.

  3. If it was the transmission breather, the oil shouldn't ever be black. It usually goes grey from clutch contamination.

    Far more likely to be unburnt oil/carbon draining from the exhaust powervalve vent hose. Thats BLACK black.

    Perfectly normal.