2002 YZ426F Overflow question

1 reply to this topic
  • Backspert

Posted December 23, 2004 - 07:40 AM


I everyone, please excuse this question if it sounds basic, but I am new to the high compression 4 strokes (previous KLX 300R rider) and I do not have an owners manual yet. Ok, here is the question, After riding the bike for a while and when I put it away, I notice that over the next several hours I get a slight leakage of a overflow tube. The tube is quite large (for an overflow hose), it comes off of the top of the motor and while the engine is running it blow out air/compression. The overflow is small amounts of clean oil. When I checked the oil, it was a little overfilled and I have speculations this may be the problem. Also, when changing the oil, do you drain both the engine and reservoir screws or do you need only to change the engine oil screw. Any engine priming needed when adding new oil??

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  • yz400fl1

Posted December 23, 2004 - 07:47 AM


The large black hose coming from the top of the engine is a valve train breather. Air goes in and out because of the piston going up and down. And yes it normal to have a little oil cumming out. When you change oil just drain the bolt in the frame tank and the one in the case. And change the oil filter every third time. Just do the oil strainer in the frame once a season. That thing could only catch large objects like stones, logs, and small children and if it does catch anything you have others things to worry about.

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