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85 XJ700 turns but won't start

Discussion in 'XJ Technical Chat' started by troym204, Aug 9, 2017.

  1. troym204

    troym204 Member

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    85 XJ700 won't start but cranks just fine, wondering where to start.

    Any insights? Thanks.
     
    Last edited: Aug 9, 2017
  2. hogfiddles

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

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    If your battery isn't strong enough anymore, it can crank but it won't fire.
    How old is the battery?
    Did you check the voltage drop when starting?
    Did you try pop-starting it?
    Did you clean the carbs?
    How Many miles on it?
    Do you know when the valve shims were last checked?
     
  3. troym204

    troym204 Member

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    The battery was replaced last year, voltage check tonight.
    No.
    No.
    11,000
    No.
     
  4. troym204

    troym204 Member

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    Just popped it, bogged down not idling well. Had to pop it again when I hit a stop coming back around in the neighborhood. Can you recomend a good guide to cleaning my carbs?
     
  5. Stumplifter

    Stumplifter Well-Known Member

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    This:
    http://xjbikes.com/forums/threads/in-the-church-of-clean.14692/

    Get your rebuild parts from XJ4Ever, link in the upper right hand corner.
     
  6. hogfiddles

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

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    If you get stuck, I do offer total rebuild service. Send me a private conversation if interested
     
  7. troym204

    troym204 Member

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    So I popped it and ran it around a few times to warm it up and it would sit at an idle, I let it run outside for a few minutes while I ran in and came out to smoke coming off of the engine from where the exhaust meets the engine. Seems as though something may have even leaked where the red seal is, which I'm wondering what exactly that red stuff is anyways. Thanks hogfiddle.
     

    Attached Files:

  8. hogfiddles

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

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    Looks like someone had the head off at some time......but--very possible that there is light oil leak and someone was trying to smear some rtv in to the joint to do a 'poor man's repair".

    BUT---if you look carefully--it appears to be the typical 'valve cover leak', and the oil simply runs down to the head gasket level, wicks across, then burns off, but makes everyone think it's a blown engine in the meantime.

    Did you check your battery's voltage drop yet?
     
  9. jsngrimm

    jsngrimm Member

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    Don't mean to jack this thread, the typical valve cover gasket leak there isn't going to wreck my engine if I run it like that is it? Of course I need to and will replace my valve cover gasket but in the meantime it won't cause any damage? Some guy at a gas station claimed my engine was going to explode because of the quite minimal leaking around my valve cover lol
     
  10. hogfiddles

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

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    The guy at the gas station is an idiot.

    Unless you're running your engine dry, and failing to check the oil level in the window, you're going to be fine. Just pay attention to the level, and be ready to clean oil off of your knees from the wind spreading it around
     
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  11. jsngrimm

    jsngrimm Member

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    Yup I figured as much :rolleyes: at first he thought it was a leak at the head which of course could hurt the motor but I have confirmed it's just some oil seeping around the valve covers, the valvetrain is certainly getting oil it's not like it's just pouring out of there. Sight glass is dirty so it's a little hard to see but every oil change pretty much the same amount of oil I put in comes back out and the oil light has never come on. I put that little bit extra oil in every time anyway, to make sure it doesn't slosh around when braking and turn the light on
     
  12. troym204

    troym204 Member

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    Makes sense as the previous owner mentioned keeping an eye on the oil level, not a problem it will give me something to do during the winter months. I've seen talk of these service manuals, is it the Haynes I want to purchase?

    The voltage drop will be checked this evening.
     
  13. tabaka45

    tabaka45 Well-Known Member

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  14. troym204

    troym204 Member

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    So I checked the battery, everything is fine it also seems to be charging just fine as well. Could it have been to hot to start? That would leave me to believe its some sort of electrical failure due to the heat possibly, just not sure what could have failed. It fired up this evening no problem. It may have fallen flat at the stop sign after I popped it because I had just got it running, which is common for this bike with what seems like fouled up carbs.

    Thanks tabaka!
     
  15. Timbox

    Timbox Well-Known Member

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    Take those carbs to Church, you will love how it runs after a good cleaning. Don't do a fast job on them or you will be pulling them off again and doing it all over. The link above is the way to go (Stumplifter) if you want to do it yourself. You will want to check the valves too, between the carbs and good speck valves she should run like a dream.

    If you think you are having electrical issues carefully start to take apart each connector (one at a time) on the wiring harness and clean them up. I would disconnect the batter before you start as not to blow a fuse or hurt anything else. Get some electric grease and dab some on the connections, it will really help.
     
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  16. Nuch

    Nuch Well-Known Member

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    Listen to good advice. If you have patience and take it one step at a time, You'll never regret your efforts.

    I was initially scared of the process. I pulled the carb set and only did a MINIMAL rebuild... (clean bowls, enrichment circuit,replace bowl gaskets, needle valves, seats, etc.) In other words, I did not split the carbs apart and replace the things that you can only replace by complete disassembly. It was better, but not great... My sub-par results gave me the courage to bite the bullet, pull the carbs again and do the job right.

    With the carbs done and the other gremlins dealt with over time, she purrs like a kitten now...

    Check your valve clearances and while you're in there, clean the contact surfaces (edge? face? whatever you want to call it) of both the head and the valve cover... then put in a fresh gasket. Your smoking issue could be the oil that is escaping and then burning off on the outside of the engine. It's also a good idea to replace your "doughnut" washers that hold down the cover. No doubt the ones you have are squashed and will not hold down your cover like they should with a new gasket. As others have suggested, Chacal/XJ4ever (top right hand corner of every page) is the goto person. He has the parts and more importantly the seemingly limitless knowledge about these bikes.
     
    Last edited: Aug 11, 2017
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  17. troym204

    troym204 Member

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    Take em to Church I love it. Thanks for the advice Tim I should probably do that anyways.

    Im curious Nuch how many hours roughly do you think you spent on the full rebuild? I would like to do it myself but have time constraints (pregnant wife, basement remodel getting ready to take place, work etc etc..), and if I tear it down I will go the whole nine, valve clearances, take the head off etc.. I am mechanically inclined and have always worked on my own vehicles so it being a somewhat daunting task after reading the Church manual its a task I am willing to undertake.

    Someone mentioned just running some sea foam through it to get me through the rest of the season, Im new to bikes and I'm always inclined to take advice from multiple sources before making a decision.
     
  18. Stumplifter

    Stumplifter Well-Known Member

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    too late for Seafoam... after you properly clean the carbs you can use it as a preventative.

    Some people here can Church clean a rack in hours.
    I am not one of those. They were off the bike for several weeks, took my time, pictures, sketches, notes, etc. A couple hours here and a couple hours there, asked questions here. Finished it and sill had to take the rack off twice.. Next time (in another 30 years) I will be much more betterer.

    So to (kinda) answer your question - you are mechanically inclined that is good, you WANT to do your own work, that is GREAT. Carbs can easily be done in whatever stages you can fit in your schedule - just stay organized as you go through them, valve clearances same thing (although that is usually about a two beer project), taking the head off... why you wanna do that?
     
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  19. Nuch

    Nuch Well-Known Member

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    The timeline for a rebuild will be different for everyone. It took me a weekend to do mine. Keep in mind that was the SECOND go around because the first time I had the carbs off the bike, the job wasn’t nearly done. But it did help for the second time as I was familiar with most of the internals.

    We have 4 carbs to deal with. Some people believe it is better to do a total dismantle, clean everything, replace the replaceable parts and then put everything back together.

    I didn’t do it that way. As I recall, I:
    1.) pulled the carbs

    2.) removed everything that was removable from the set while they were together

    3.) split the rack and dealt with one carb at a time. In other words, once split, continue to dismantle ONE CARB, soak, rinse, soak, rinse (carb cleaner) then replace replaceable parts (throttle shaft seals while it is still a single), then reassemble. Then… go to the next carb.

    I did this as I was more comfortable having the other untouched carbs to refer to if I had a problem. Granted, they differ from each other in some way, but it is a good reference…

    4.) re assemble the rack once all 4 carbs are zestfully clean. Now is a good time to put in NEW fuel o-rings.

    5.) Give yourself a MAN pat on the back… you just rebuilt your own carbs. You probably don’t even know anyone that can do the same now-a-days. I don’t… that is of course with the exception of the folks on this forum.

    Take copious pictures along the way to refer back to… multiple angles of the same thing… I took over 200…
    Draw diagrams, write notes… Anything you think you might want to know later… write it down.

    01_exploded_view.jpg
    Get yourself a nice clean piece of cardboard and cover your workspace with it. I placed everything in order with respect to each other and wrote right on the card board.


    02_2dirty_2clean.jpg
    Here is a shot half way through. 2 dirty and 2 clean and completed! I took extra time to do the first one... I think I spent a good part of Saturday doing #1. Here and there I walked away from it as it soaked. I believe once I had a good handle on what to do, I got #'s 2, 3 & 4 done on Sunday.

    03_3_favorites.jpg
    Don't forget to enjoy a beverage. It is a hobby after all! I just can't bring myself to really like wood chuck... Though Hogfiddles makes a mean hard cider... Sooo Good.

    04_carb_rack.jpg
    Build a carb rack out of PVC. It was key to my wet setting after re assembly.

    Get everything you need to do the complete job before you start. Chacal (top right corner of every page) can set you up with everything. He did for me. A++

    Good luck.

    Keep asking questions... You'll get answers.
     
    Last edited: Aug 11, 2017
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  20. k-moe

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

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    You don't need to take the head off unless there is something wrong with the head, head gasket, or some other internal component.

    Also, the work does not have to be done all at once. Make it a leisurely project, and plan on riding in the Spring. Doing it all right the first time pays dividends.

    The Information Overload Hour
     
    Last edited: Aug 11, 2017

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