crankcase breather

2 replies to this topic
  • yamahazinger

Posted August 11, 2005 - 07:48 AM


i have heard and wondered for a long time what a crankcase breather does and where is it located? Also where does it connect into the crankcase? I have an 02 yz250 and am wondering if mine has one. I dont think so because i have never seen it. If anyone knows id appreciate an answer. thanks :D

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  • CHEEZE13

Posted August 11, 2005 - 08:20 AM


Do a search in this forum on cyclinder head breather hose and read all you want.

  • grayracer513

Posted August 11, 2005 - 09:11 AM


It's the black, 1/2" hose on the left side that connects to the cam cover. Your engine displaces 250cc on both the top and the bottom of the piston, and some combustion gases always get past the rings. The breather gives all of that somewhere to go.

If you actually have a YZ250, and not a 250F, you don't have one. It's a two-stroke, and the craankcase is part of the intake stream.

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