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1982 xj650 Cranks but wont start 2 days after buying.

Discussion in 'XJ Technical Chat' started by anthony771, Nov 15, 2018.

  1. anthony771

    anthony771 Member

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    Hello, I bought a 1982 xj650 maxim 2 days ago. It ran beautifully and started right up when I was testing it before buying. Rode it home 25 miles and had no issues, seemed to run just fine.

    Its now 2 days later and it cranks but doesn't start. I tested spark on all 4 plugs and they looked nice and blue.
    I can smell gasoline when cranking it, also sprayed starting fluid in the spark plug holes but didnt hear a sound.

    I don't get how it would start right up before but now nothing. I tried half choke, full choke, no choke. Idk what to do. Is it possible I have the petcock on the wrong setting??

    If you need more info or would like videos id be happy to post. Please help me I feel like I just got ripped off...

    Thanks. -Anthony
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    first do not use throttle it should start with out it just the choke.
    second is there gas in the tank?

    put bike on centerstand and check oil level in the sight glass.

    could be your battery is weak and needs charging or replacment.
    hook a meter to battery and record voltage then press starter button does it drop below 10 volts if it does tci will not fire.
    if you leave the key on for about a minute do you get a back fire?

    petcock has 3 positions run/on, reserve and prime if tank is full it should run in all 3 positions


    still have glass fuses? could be bad connections at ignition fuse
     
  3. anthony771

    anthony771 Member

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    Okay, tank is full. I was trying to use the gas to start it. Maybe I flooded it.

    I hooked my multimeter up and pressed the starter and all of a sudden it started up. I have no idea why as I've been trying to start it for the last hour. Even had the choke off.
    I am uploading a video of it running to Google drive. Will reply once it's done

    Also, what do you mean backfire if I leave the key on for a minute?? Will it just ignite?

    Thank you
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    first thing is keep a notebook
    when you have it running test your charging system

    in this thread you will find the specs
    The Ultimate Relay, Switch, Sensor, and Diodes Guide

    make sure your battery cables are clean and tight (hooked meter to it and it started)
     
  5. anthony771

    anthony771 Member

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    Wow thanks so much. I'll have to test it tomorrow as it's too late and I don't want to piss the neighborhood off.


    What confuses me is when I could not get it to start I still had good spark. Plugs are very new and spark was blue.

    The seller said he rebuilt and tuned the carbs. I'm guessing he did a slop job at it.

    It won't let me post a link so I will message through video to you.
     
  6. Jetfixer

    Jetfixer Well-Known Member

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    Okay first unless you know or trust the PO , you should check it over . One item check the petcock if it is factory ,then there is a vacuum line going to it, make sure it is in the ON position. If it is in the PRI, RES fuel will flow constantly , if needle is not fully seating , you can leak a whole tank of gas into the crank case. If it is an aftermarket petcock probably has ON ,OFF,RES you have to put it to off when not in use. This can also foul the plugs verified by pulling plugs if one or more are wet. Highly suggest you go to top of page click on xj4ever read the information overload hour , purchase a service manual . Do your research on the site and don't be afraid to ask questions , if your afraid to ask a member on the public forum, start an IM message , I've helped a few in the manner . Good luck
     
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  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Emphasis mine.
     
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  8. anthony771

    anthony771 Member

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    Thanks for all this info. The Petcock seems stock, and I left it in on position the past 2 days.

    But, the vacume line is missing. I see where the port for it is but it's uncapped. I'll attach a picture.
     

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  9. Colin 85 700

    Colin 85 700 Active Member

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    The vacuum line must attach to a port or manifold of lines on thee intake.
    Engine vacuum opens the petcock, safety so if the bike dumps n stalls it shuts off fuel.
    For now try the PRI setting, this bypasses the vaccuum diaphram alliwing fuel to the carbs.
    Hope this helps :)
     
  10. Colin 85 700

    Colin 85 700 Active Member

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    To note: when cranking the ON setting barely allows gas in till the engine starts.
    Hence PRI setting, or prime, to fill carbs if they hsve been serviced or the bike has been sitting and they are empty, so you dont have to crank the bike for an hour to fill the carbs. :)
    Contrary to Jetfixer, my bike appears to still shut off fuel in the RES or reserve setting when not running try prime. ;)
     
  11. anthony771

    anthony771 Member

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    I'll try that tomorrow and will report back.


    I really really appreciate all your guys help. Its amazing how many good post I got on here so quickly. Makes me happy.


    You guys have a good evening.
     
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  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    cap off the port on the carb intake manifolds it can make it hard to start if not capped
     
  13. XJ550H

    XJ550H Well-Known Member Premium Member

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  14. anthony771

    anthony771 Member

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    Is this the port you are talking about?? It looks already capped.
     

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  15. anthony771

    anthony771 Member

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    Also am I going crazy or does it seem like there is no oil in this bike???? I can't tell if the sightglass is foggy or if I nee
    d oil.

    The bike starts fine now, only need a touch of choke. However, I need to obisobio change oil and oil filter and do that valve thing people talk about. I will not start it til I get fresh oil in her.
     

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  16. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Well in the pic, the oil is low,BUT--are you on the center stand or side stand?if it's center stand you're waay low. If it's on the side stand, you will see the oil leve go up just standing the bike upright. Put it on the center stand on a leve surface. THEN check the glass

    As far as the petcock....the vac line operates the RUN and RES part of the petcock. The PRI is a free-flowing setting. If all for vacuum ports are capped, you have no line goin to the petcock. So the petcock should be set to PRI in order to ride, but you need to make sure to set it back to RUN or RES when you stop. Otherwise, you could load up the crankcase if you have any leak petcock or floats......best thing to do---get the vac line hooked back up and verify the petcock is in good working order.

    Next thing.....check the voltage of the batter WHILE you're cranking. Let us know what it is. What you describe is ALSO symptoms of a bad battery.
     
  17. anthony771

    anthony771 Member

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    It's on the centerstand. I'll do an oil change asap.
     
  18. anthony771

    anthony771 Member

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    I have not noticed any leaks if I park it on ON. Bike runs good on the PRI setting. Is it a bad idea to leave it how it is for now? I have other more important things to fix first so I figure if PRI works fine I'll use that.

    The one time I measured the battery while cranking it didn't go below 11 volts but it started.

    I should do this test again. Would it be a bad idea to do the crank test with my oil that low? I think I should at least fill it first.


    Thank you guys so much for all this help.
     
  19. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Add oil. It could be your is low enough to trigger a no-start.

    Leave it on prime while running. DO NOT leave it on prime when you shut it off
     
  20. anthony771

    anthony771 Member

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    Okay cool. I gotta find a place that sells motorcycle oil today. Any recommendations for oil?? I should probably use the search function for that.


    I really appreciate your help guys. I've got some stuff to do this morning but when I get free time I will try the things you've told me.
     

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