Jump to content


  • Content Count

  • Joined

  • Last visited

About mike_kronenberg

  • Rank
    TT Newbie

Profile Information

  • Location
  1. mike_kronenberg

    WR400 vent hose oil leak

    he, he Was wondering why the oil dip stick resisted so much getting back into the oil tank. And I thought it was just me with a six pack related hallucination
  2. mike_kronenberg

    WR400 vent hose oil leak

    Just did a full oil and filter change and now used Honda 10W40. Went for a test run around the neighborhood (neighboors love it when I do that, really ). Interestingly the vent hose oil leak seem to have subsided, at least it's not as obvious (only saw one drop). I had full sunthetic before -- weird, could oil type do that? I'll still have the leak down test done at the local Yamaha dealer tomorrow to get a more complete picture.
  3. mike_kronenberg

    WR400 vent hose oil leak

    I'll follow up with the info found during the leak test. My current guess is that the rings are worm and the engine is experiencing some blow-by which exists through the vent hose with such force that oil is pushed out as well. Weird thing is that I would expect some major power loss from the blow-by but I don't find it noticeable. There is still all the power I can handle
  4. mike_kronenberg

    WR400 vent hose oil leak

    Thanks for the feedback -- I have a leak test scheduled for Saturday to find out how tight the valves and piston/rings are. Will see what comes out of this. My concern about losing oil the way my WR400 durrently does (1/2 quart in 2 hours of hard riding) is that there isn't all that much oil in the system in the first place... Then again, this is my first 4-stroke and I'm discovering things as I go. Mike
  5. mike_kronenberg

    WR400 vent hose oil leak

    My '98 WR400 is dripping oil from its vent hose (vent hose is connected to the top of the valve cover). It's not a continuous leak under the bike, but drop by drop it adds up and has me now concerned. It'll probably leak 1/2 quart in 2 hours of hard riding. I'm guessing that I'm not the first one who has experienced this and would appreciate your feedback to understand what could be causing this. My analyses would suggest that either: - Piston rings are shot and some blow by gases leak into the crankcase which then could blow oil out of the vent hose. - Or, some valve seal is shot and gas is escaping to the top of the cylinder head pushing oil out as it makes its way out through the vent hose (just read this possibility in this month's Motocross Action magazine). Either way, I'll need to open the engine but I'm wondering what would typically be causing a leak as described above. Your thoughts? -Mike