XR600R dual sport build. Will it run?

Discussion in 'Some Assembly Required' started by Juddvong, Aug 19, 2021.

  1. Ron50

    Ron50 Long timer

    Joined:
    Oct 12, 2008
    Oddometer:
    4,697
    Location:
    Canberra
    If you remove the screw cap you can see whether the mechanism clicks as you slowly turn the engine over.

    If it doesn't click and allow the valve to fully close it is faulty.

    Of course, if the bike is in the intermittent starting mode this test won't show anything but normal operation.

    So you'll have to wait until it won't start again, remove the cap then check whether the right side exhaust valve has free play under the rocker with the valve closed.

    If it doesn't, there's your problem; if it does, move on to looking elsewhere.
    #21
  2. bork

    bork Been here awhile

    Joined:
    Oct 30, 2013
    Oddometer:
    825
    If you want to remove valves, and you are near an Auto Zone or Advance Auto Parts, they have a loaner spring compressor. :thumb
    #22
  3. Juddvong

    Juddvong Adventurer

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    Jun 2, 2014
    Oddometer:
    48
    The big reveal! This part is always exciting. The head looks clean. I still have to tear it down more to make sure everything is in spec. Is this a factory cam? Looks like it doesn't have the auto decomp. The cylinder looks good to me. I couldn't really see anything wrong with it. The cross hatching is still present. The valves had a lot of build up but the edges didn't look worn. The valve seats aren't pitted. I'm thinking I can lap the valves and install new gaskets? Kind of at the tough position of already having everything apart...
    PXL_20210824_163829000.jpg PXL_20210824_163836731.jpg PXL_20210824_163846355.jpg

    Attached Files:

    #23
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  4. villageidiot

    villageidiot Long timer Supporter

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    looks like its been runnin wild ass rich and or burning copius amounts of oil
    #24
  5. Juddvong

    Juddvong Adventurer

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    I think rich, I never noticed any smoke coming from the tail pipe. There was a lot of issues with tuning the Edelbrock carb that was on it. I'm thinking that's where all the build up came from.
    #25
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  6. *perko

    *perko Adventurer

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    Aug 31, 2015
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    Definitely not factory and no decomp, looks like Hotcams by the part number and a google search.

    I'd be leaning towards cleaning it up, lap the valves and reassemble, you could check ring gap it you wanted but judging by the bore it would most likely be ok.
    I would think there's a good chance all that carbon is holding valves open, check the valve spring lengths while you're in there.

    Make sure to only use the genuine metal gaskets for the valve cover as they set the bearing clearance for the cam, I've often just reused the old one with some non-hardening sealant on the faces.
    #26
  7. xrjac

    xrjac XRJAC

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    Jul 21, 2017
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    Sorry for the late reply, run some carb cleaner through the valve guildes replace valve seals and change oil a couple times. 500 miles appart. I've had my valves stick open due to gummed up guides in the past. Same symptom. Valves partially stuck open. Was after being stored for a while. Change gas too.
    #27
  8. Zuber

    Zuber Zoob

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    Also helps to pre-mix some two stroke oil in the gas.
    #28
  9. bork

    bork Been here awhile

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    Oct 30, 2013
    Oddometer:
    825
    Update please.
    #29
  10. zipweee

    zipweee Been here awhile

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    Get the valves right for sure but also might want to read up on the pulse generator. It can cause starting problems on the xr650ls.
    #30
  11. Juddvong

    Juddvong Adventurer

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    Jun 2, 2014
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    48
    Sorry, I took the easy way out. I bought a new set of Ferra +1mm valves and sent the head off to a machine shop to get properly cut in. I started cleaning the valves that were in it but I couldn't get the debris or coating off the intake valves good enough. The machine shop said it would take 4-5 weeks since they're so busy. It's been 5 and I'm just waiting to hear from them.
    #31
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  12. xrjac

    xrjac XRJAC

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    Good move! Hopefully you'll have it back soon. Impatient me would call for follow up. Sometimes things happen in the waiting line.
    #32
  13. xrjac

    xrjac XRJAC

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    #33
  14. xrjac

    xrjac XRJAC

    Joined:
    Jul 21, 2017
    Oddometer:
    12
    Location:
    Conway, AR
    Any updates?
    #34