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XR650r mystery

Discussion in 'Thumpers' started by Basicrider, Nov 15, 2018.

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  1. Basicrider

    Basicrider n00b

    Joined:
    Nov 15, 2018
    Oddometer:
    7
    Location:
    North Carolina
    A3DDC658-FC2D-4A9B-A5F9-C7C59F0DEEB1.jpeg I have a 2000 xr650r that won’t run. Exhaust is uncorked and rubber restictor removed from air box by Previous owner.
    Did the basic checks (gas, air, spark), cleaned the carb, replaced spark plug, checked wiring. Got it to start, but ran poorly more of a pop pop pop versus a purr. Tried re jetting based off the advice posted here but couldn’t get it started so now it is back to stock jets. Did the valve adjustment, now it won’t start. (Maybe a coincidence) when trying to start there is a backfire every other kick it seems like. When it ran you could see some black smoke. I’ve spent hours and weeks researching and tinkering to no avail. I have no mechanical experts in my area. I took the top end off to inspect valves and cylinder, they seem fine minus the black soot build up.( I think that means it’s been running lean) so back to needing bigger jets 175 and a 68s and looking for a vacuum leak but that’s difficult when it won’t start. Please help. 09E77CBF-DD8A-4DA9-9BE2-2FFD7AF4E9D0.jpeg 0FA40D5C-2B9B-4379-B822-DF58878EC287.jpeg 0FA40D5C-2B9B-4379-B822-DF58878EC287.jpeg A4648DF6-4AFA-4316-82D5-FC6C0477518E.jpeg
    #1
  2. GSXR

    GSXR Trail Rider

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    Oddometer:
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    Location:
    Sunshine Coast, Australia
    Basic,
    My next step would be to lay the head on its side and check valve seat leakage by pouring a bit of fuel into the relevant ports. Hard to tell in the pics if the valves have recessed into the head. Wire brush it a bit and re-post pics of valves if you like.
    Don't stress about the soot.... it is a sign that it was running very rich, as in your other description.

    Re choke: up is on, down is off. Sure you weren't running it with the choke up? Would it idle?
    #2
    Basicrider and 2ndA732 like this.
  3. grigby

    grigby Adventurer

    Joined:
    Dec 7, 2012
    Oddometer:
    58
    Location:
    Southlake, TX
    It's too rich, I had a similar problem after cleaning the carb. The needle jet fell out and I did not notice it was missing, would pop and difficult to start. Check to make sure it's in the carb.
    upload_2018-11-15_16-33-44.png
    #3
  4. kta

    kta Riding Everything Everywhere

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    Sep 10, 2007
    Oddometer:
    670
    Location:
    Guatemala
    Did you check your timing to make sure it didn't jump a tooth?
    #4
    sprouty115 likes this.
  5. kta

    kta Riding Everything Everywhere

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    Sep 10, 2007
    Oddometer:
    670
    Location:
    Guatemala
    You should also use a fresh spark plug. If you are rich like that the plug can foul or fire weak.
    #5
  6. larryboy

    larryboy Stable genius.

    Joined:
    Jan 9, 2005
    Oddometer:
    27,753
    Location:
    Über Alles,California
    I had the jam nut come loose on the needle jet holder one time, same symptoms. If you've been changing main jets it's very likely the jam nut is loose now.
    #6
  7. Basicrider

    Basicrider n00b

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    Oddometer:
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    North Carolina
    Thanks Guys, I’ve got some work to do and will report back with results.
    #7
  8. Basicrider

    Basicrider n00b

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    Is that just making sure TDC on flywheel and timing marks level on cam shaft gear?
    #8
  9. 2ndA732

    2ndA732 ...not be infringed

    Joined:
    Mar 11, 2018
    Oddometer:
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    Location:
    CA
    When it does run if it is a bit wonky check to make sure your float bowl is set correctly. At that age, it's simpler just to replace the float valve that rests in the carb. Shouldn't relate to getting the thing started, but it will relate to idling. Also ensure it's put in the right way. this is a great book to own: Clymers 2000-2007 Honda XR650R Troubleshooting . Maintenance . Repair.
    #9
    Basicrider likes this.
  10. Basicrider

    Basicrider n00b

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    Nov 15, 2018
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    A8DBE24B-46D3-4453-9C28-D20AAC9745D2.jpeg Ok so I’ve got the float set back to standard. In the process of cleaning everything and putting it back to get her. Cylinder has minor pitting. Valves look a little rougher. Also when I put th can back in all I do is make sure TDC on the fly, lobs down, gear with timing marks parallel with head.
    #10
  11. 2ndA732

    2ndA732 ...not be infringed

    Joined:
    Mar 11, 2018
    Oddometer:
    172
    Location:
    CA
    ^ looks a little better. How are the valve seats now? Have you tried to fire her up again, yet?
    #11
  12. Bowber

    Bowber Been here awhile

    Joined:
    Feb 27, 2012
    Oddometer:
    563
    Location:
    Cumbria, UK
    Flywheel has come loose and sheared the key?

    Steve
    #12
    RideFreak likes this.
  13. Basicrider

    Basicrider n00b

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    Key? Flywheel seems tight
    #13
  14. Basicrider

    Basicrider n00b

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    Poured fuel in the ports and left on side with no leaks. Got her back together today no luck on firing back up. Leaving for work be back in a few days to trouble shoot
    #14
  15. RideFreak

    RideFreak Torque Junky

    Joined:
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    Oddometer:
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    Location:
    Out in the NM Dez somewhere
    You wouldn't feel it or be able to tell except by checking the timing marks in relation to piston location, it wont be loose to the feel. The popping and starting issues lead me to believe it's a timing issue since the valves aren't leaking. I suspect one of the following;
    Like steve said, slipped flywheel/woodruff key issue (easy check with a flywheel puller)
    Valves were adjusted at the wrong TDC.
    Cam timing is off.
    Bad CDI (unlikely, they're pretty bulletproof)

    If I suspected a carb or fuel issue, I'd turn off the fuel, drain the carb, do the clearing drill; 10 kicks, compression release in, throttle wide open. Then let it sit for 10min then with the side cover off and the air filter removed I'd spray a couple small squirts of fuel down the throat of the carb with the throttle open. Then give it a few kicks, it should fire and run a couple revolutions. If it backfires then it's almost surely the ignition/cam timing issue. By leaving the gas off and clearing the motor you basically have taken the fuel part of the carb of the equation.

    But I'd be willing to bet this isn't a carb/fuel issue.
    #15
  16. Bowber

    Bowber Been here awhile

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    Feb 27, 2012
    Oddometer:
    563
    Location:
    Cumbria, UK
    As Ridefreak said take off flywheel to check, I've had similar problems and it's usually turned out to be ignition related, slipped flywheel is the easy one to troubleshoot but I've had a Honda Dominator that went sick and eventually i had to replace the pulse coil which got it running but it still wasn't right so ibought a new CDI, ran fine after that.
    Fortunatly it was just as Honda UK brought down the price of spares so the CDI reduced overnight from something like £180 to £95. I wouldn't have bother otherwise as this was in the mid 90s and I had very little spare cash.
    Another 2 bikes turned out to be pulse coil, 1 was burnt out source coil (easy to diagnose) the pulse coil ones are hard to diagnose (unless you have spares handy) as the motor would have a spark and it would be timed right but the voltage out and how it happens controls the timing and the correct opening of the thyristor in the CDI.

    Steve
    #16
  17. TJE

    TJE Space Emperor

    Joined:
    Sep 17, 2009
    Oddometer:
    88
    Following! I had similar symptoms before I dismantled the entire engine and replaced all parts that could wear. I'm almost at the point where I can start it up for the first time, so curious about what you think cause your problems.
    #17
  18. Basicrider

    Basicrider n00b

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    Nov 15, 2018
    Oddometer:
    7
    Location:
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    Thanks for all the help. It’s come time to send it off to a shop. Got a ktm exc for the interim.
    #18