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oil filter check valve

Discussion in 'The Garage' started by pjmule, Sep 25, 2011.

  1. pjmule

    pjmule XS650 Member

    The bolt that holds the oil filter on the right side has a check valve. Should the screw be tightened till it stops or is the tension adjustable on the ball and spring? When I took mine out I noticed that the screw wasn't tight.
  2. pamcopete

    pamcopete Ride.Enjoy.Life is Simple


    That is the pressure relief or bypass valve. I do not know of a published procedure to set it. The nominal pressure of the system is 14 PSI, but you will only encounter that with a cold engine. Just set the screw about at the half way point.
  3. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    IIRC the screw is tightened till it seats, the spring sets the correct relief pressure.
  4. pjmule

    pjmule XS650 Member

    Gary, what's IIRC ?
  5. XSLeo

    XSLeo XS650 Guru Top Contributor

    I always set it just flush with the end of the bolt. Tighten till it stops takes all the play out of the spring and the ball can't move.
  6. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    um oh yeah; If I Remember Correctly

    Sounds like I don't :shrug:
  7. pamcopete

    pamcopete Ride.Enjoy.Life is Simple

    Well, just to add to the confusion, I replaced my ball and spring with just a threaded stud that eliminates the pressure relief function. I didn't want junk bypassing the filter on startup.

    The bypass is there supposedly to prevent engine damage due to oil starvation in the event that the screen gets plugged up with some junk from a self destructing engine. The problem with that idea is that the bypass would open and let the junk bypass the filter in order to save the engine? I don't think so.

    Also, the junk would have to get past the sump filter, so that could only happen if the sump filter had a hole in it, which it often does, but I think that the hole is made by the increased flow of thick cold oil and that the flow increases when the bypass valve opens, so keeping it closed will help prevent a hole in the sump screen, except that not having a bypass valve means that you should have an oil pressure gage so you do not exceed 14 PSI when the oil is cold. I did install an oil pressure gage when I eliminated the bypass valve and my sump screen lasted 13 years and 60,000 miles so I guess it works.
  8. pjmule

    pjmule XS650 Member

    How do you not exceed 14 PSI when the oil is cold with an oil pressure gage?
  9. pamcopete

    pamcopete Ride.Enjoy.Life is Simple


    Oil pressure is directly proportional to engine speed, so I keep the revs down during warm up.The gage is mounted right in front of me. I keep an eye on the pressure during warm up and don't move until I know it will not exceed 14 PSI at 3,000 RPM. I keep the revs down and shift gears when the pressure gets to 14 PSI until the oil warms up. After the engine warms up, the pressure is about 5 to 7 PSI @ 3,000 RPM, so no need to watch it anymore.

    The other purpose of the bypass valve is to protect the filter from excessive pressure when the oil is cold, but the sump screen does not have a bypass valve, so the cold oil flow is actually increased when the bypass opens and that is what I think holes the sump screen. The early models had the bypass valve installed in the oil pump, so when that valve opened, it relieved pressure on both the sump screen and the filter. Don't know why Yamaha changed that design, except perhaps to save some production costs.

  10. pjmule

    pjmule XS650 Member

    Wow, thanks for the education! I never thought a simple question about tension on a ball and spring could be so helpful .
  11. 5twins

    5twins XS650 Guru Top Contributor

    I remember reading a post a few years back on one of these forums from a guy who bought a new 650 back in the day. He said his check valve screw was set flush with the bolt top from the factory.
  12. Interesting thread, I've left the setting of the pressure relief valve as I found it, what I've noticed yesterday when doing my 1000 mile oil change was the setting had moved, the screw was nearly flush with the face of the screen.
    So the mechanic in me was looking at why? Did a quick search on the forum and didn't find anything definitive about the setting. Without a pressure gauge on the bike it's difficult to define what the correct position is.
    Also noticed the main sump plate screen is slightly deformed, so I am assuming that there has been a higher flow rate going through. Like others I warm my engine up before riding, so that leads me to believe that the further the screw is out, the less pressure is obtained at the bypass point?

    • So do we know what the factory setting is at all?
    • Is there a recommended setting?
    I would like to resolve this so that I'am not going to be giving money away for the sump plate screens, they are not cheap.....any input appreciated

  13. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Last edited: Oct 7, 2016
  14. weekendrider

    weekendrider Iron Horse cowboy Top Contributor

    S.W. MO

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