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82 650 Maxim

Discussion in 'XJ Technical Chat' started by Chitwood, Apr 13, 2018.

  1. Chitwood

    Chitwood Well-Known Member

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    So last night I finally got a chance to fire the bike up after taking the carbs to church, deluxe rebuild kit from chacal, throttle shaft seals, the whole bit. Wet set the floats. Everything is good to go in the carbs, slides passed the clunk test, etc. Valve clearances are in spec. New battery that is up to snuff. Fired up pretty well. As it was running in the first minute or so I had my hands on the head pipes and noticed that #4 wasn't getting warm. I let it run for about 20 min and in that time it did finally get hot but still didn't sound like it was hitting on all 4 until I gave it throttle. Once at idle, which it does idle all by itself, something it did not do last year before carb overhaul it still seems to not be hitting on #4. Of course I had run out of play in the garage time as I had to get the boy in the house and through the shower for his school night routine so I didn't have much chance to do any further diagnosis other than to pull the plug wire off 4 and check for spark with a screwdriver against the head. Nice blue consistent spark jumping from the screwdriver to the head. Tonight I will be pulling the plug to inspect as well as performing some resistance checks on the ignition system. My question is what else should I be looking for as it only seems to be isolated to #4? I will probably also bring a compression tester home as I don't recall having ever done that. Another note is that I have not yet gotten a chance to perform a running synch or to adjust any of the pilot mixture screws. They are all currently set at 2.5 turns out. (Fine threads on the mixture screws) I'm really hoping I don't have to pull the carbs out again since everything was set just right before putting them on. Am I on the right track? Any ideas or advice? Slightly frustrated here...
     
  2. Timbox

    Timbox Active Member

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    Do you think #4 is firing once you give it some throttle? If so could be the bench sync if off on #4. If that is off a little then at idle it might not tire and get the pipe hot. Now this is just if it only happens at idle and when you flip the throttle it is firing and getting the pipe hot.

    The frustration is normal IMHO, it takes some playing with these carbs and all the rest of the components that get these bikes running well. Just know you are heading in the right direction and you are so close to the satisfaction of listening to her prrrr.

    I pulled my carbs more times then I want to admit to get them running on my "X".
     
  3. Chitwood

    Chitwood Well-Known Member

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    It's hard to tell but when I give it throttle it seems smooth not missing like it does at idle. Like I said it eventually does get hot just takes awhile. I am hoping that a synch will help followed by some pilot mix adjustments and synch again. Just want to make sure I'm not overlooking something obvious and headed on the right path
     
  4. Jetfixer

    Jetfixer Well-Known Member

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    Try new plugs...I had the same thing and last year my 71VW had a bad plug...after replacing plug wires and cap and rotor ...pulled plug looked fine had not been in there that long ...put new plug in and ran great. On my seca number 1 cylinder pipe was cold , took cap off trimmed plug wire put cap back on and still cold , plug looked ok so put in new plugs and drum roll she ran great . For giggles I kept the suspect plug from the others and put it back in only running on 3 so this verified it. You could try swapping plugs around and see if it follows to a cold cylinder.
     
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  5. Chitwood

    Chitwood Well-Known Member

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    I was thinking of that as well. Have 4 new plugs sitting on my toolbox right now.
     
  6. tabaka45

    tabaka45 Well-Known Member

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    If you have access to a colortune it will show what is going on in that cylinder. Rather than use the new plugs I would just swap #4 with one of the others and see if the problem moves. (New plugs are really helpful in getting the pilot screws set when everything else is fine.) Run it with the “choke” on and see if it heats up faster. Have you checked for leaks around the intakes? I had a leaking intake gasket and had to open the pilot 5 turns just to get it fire. If you do have to go back inside the carbs pay special attention to the pilot circuit.
     
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  7. Chitwood

    Chitwood Well-Known Member

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    I don't have access to a colortune. I know I should probably get one. When I noticed the issue it was running on the enrichment circuit. I will be getting out the the garage later so I can check for any intake leaks, even though the boots are in good shape and the gaskets have been replaced still worth checking. I also plan on swapping plugs around or even putting a known working used one in before the new set.
     
  8. XJ550H

    XJ550H Well-Known Member Premium Member

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    swap the plug to another cylinder see if the problem follows is the quick way to check things before you start with the complicated items. also try about a 1/16 turn on #4 sync screw to open it up a little more (after you try the plug swap).

    there are a few threads on building your own sync tool , simple as just a tubing set up to tubing and glass baby bottles
     
  9. tabaka45

    tabaka45 Well-Known Member

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  10. Chitwood

    Chitwood Well-Known Member

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    Thanks for all the replies guys. Between mother nature dumping some wet heavy snow on us and painting walls at the house most of the weekend, I haven't made it to the garage to mess with anything. I do have a manometer style synch tool that I will be using. Have a trailer lined up and planning to go to my buddy's heated shop to work on that tomorrow after work
     
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  11. Chitwood

    Chitwood Well-Known Member

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    Well I am happy to say after a vacuum synch and new plugs she runs like a champ. Need to get a colortune so I can dial in the pilot screws and re-synch but she's hitting on all 4, crisp throttle response, only a very, very slight hang on decel but I don't feel it's anything to worry about as it's far improved from last year. Plan to put some miles on it when mother nature allows, read the plugs and go from there. Thanks to all for the replies/advice. Now on to the GF's 81 650...
     
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  12. Brendan2250

    Brendan2250 New Member

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    Howdy,
    In my infinite wisdom I lost Air Jet #205, cant find it anywhere on ebay/ JP cycles/etc. You guys have any input? I can easily get jet #50 and and all others, but not #205...
     
  13. Chitwood

    Chitwood Well-Known Member

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    XJ4ever. Top right corner of every page. Send Len a PM and he will hook you up.
     
  14. Chitwood

    Chitwood Well-Known Member

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    After a few minor tweaks here and there, including a colortune (thanks xj4ever!), sitting outside the garage basking in a lovely spring time evening. I am thoroughly impressed with how this bike performs and I could not have done it without the incredible group of people and knowledge base here along with stellar parts and service from xj4ever.com. Both maxims are running and performing 100% better than when I purchased them. Now that these are sorted for now I'm going to have to find another one to feed the addiction...oh wait, i still have a 750 midnight maxim in hiding...just don't tell the girlfriend...
     

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  15. Toomanybikes

    Toomanybikes Well-Known Member

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    Show us pictures of the midnight!
     
  16. Chitwood

    Chitwood Well-Known Member

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    I'll have to get some first but I absolutely will. It's definitely not original but we'll worth the 300 or so I paid for it with a title. When I get a chance to make it over there I will snap some pics and post them
     
  17. Chitwood

    Chitwood Well-Known Member

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    Is it possible to install the steels in the clutch backwards or not all the same direction and cause it to excessively wear the friction linings?
     
  18. Polock

    Polock Well-Known Member

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  19. Chitwood

    Chitwood Well-Known Member

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    Kinda what I was thinking as well but I have been searching for an explanation as to why my new clutch plates are junk after less than 500 miles. Also noting that I checked and rechecked the cable adjustment after basically every ride and soaked the new plates before install.
     
  20. Polock

    Polock Well-Known Member

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    junk as in they measure too thin or it slips and the cable is adjusted?
    did you put new springs in it?
     

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