Crank vent tube still leaking oil after new rings

27 replies to this topic
  • YZ250F_Rider

Posted October 12, 2004 - 03:00 AM


I dont recall if you mentioned it, but what oil do you use?

  • MaxAZ

Posted October 13, 2004 - 06:15 PM


RedCap Mobile 1 normally. Right now I'm just doing breakin on the rings and still using Castrol GTX 20/50. Was recommended to me for the breakin period and I've been changing it about every 60 miles. Doesn't seem to bother the clutch at all and I pounded it hard on the last to rides but it only came close to getting grabby once but very briefly. I'm sure it would have done the same with the Mobile 1 under the extreme circumstances too. Never got around to checking anything last weekend. Never even touched the bike! What's my life coming to, all work and no play makes me cranky.

  • new2blu

Posted October 13, 2004 - 06:22 PM


Does the Yamaha cylinder have to be honed when rebuilding the top end?
I haven't rebuilt one(Yamaha) yet;but have rebuilt other engines in the past.
Jus ta thought.

  • YZ250F_Rider

Posted October 13, 2004 - 06:42 PM


For what it's worth to you I can get oil from my vent tube on the 05. It doesnt drip that I know of but it's in the tube enough for me to just touch the end of it and get a film on my fingers. And I run 15-40 shell diesel oil. As long as the bike is making good power and you change the oil regularily I really wouldnt sweat it. (give the foam in the tube a thought, just pretend it's on the rag :cry: )

I personally wouldnt just swap rings and or piston without replating and honing the cylinder. It's hard to force a new set of rings to wear the same as a different set wore. and there is such little plating left (sometimes) that you run the risk of wearing it off completely in high spots with the new rings.

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  • Butta

Posted October 14, 2004 - 03:20 AM


I'm glad you are open to stupid questions, because I actually thought my bike was doing the same thing, blowing out oil through the tube even after I was done riding it. Come to find out, I had a hairline crack in the timing cover which was leaking oil and it just appeared to be out of the breather tube. Give the covers a look, see if there is a light film of oil on them or some part of them. If so, remove the cover (after draining the oil) and you should be able to see the crack, if any. I always hope it's the easy fixes!!

  • YZ250F_Rider

Posted October 14, 2004 - 03:44 AM


yep them cracks are what makes engine gaurds worth it.

  • RRmike

Posted September 02, 2005 - 02:46 PM


You ever figure this out? I got one doing the same thing, thinking of trying a different oil. Its running silkolene 10w-30

  • bob333

Posted September 02, 2005 - 06:19 PM


[quote name='lightestYZF']

2)Cam chain flingiing oil off from its trip through the sump (again not sure why this would be different unless more oil in your sump than normal - maybe different type of oils could change this some).

:D dingdingding we have a winner and all you have to do to fix this problem is take out the hose and stuff some steel wool a couple inches from the engine and put it back on and you'll be good to go :D :D

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