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Carb slide height

Discussion in 'The Garage' started by Graeme1198, Jan 11, 2020.

  1. Graeme1198

    Graeme1198 XS650 Enthusiast

    Hi guys,

    Put some mikuni vm34s on the xs this week.
    Got the TC bro’s set that come with some extra jetting etc.
    As expected I’ve had some issues with the jetting running very rich.

    Thing I can’t get my head round is the fact that the slide seems really high almost 5mm open when at idle. Is that normal?
     
  2. Graeme1198

    Graeme1198 XS650 Enthusiast

    The idle screws are basically all the way in just to note.
     
  3. 5twins

    5twins XS650 Guru Top Contributor

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    You can inadvertently install the slides backwards and then they sit too high. But they're very high. The motor will race and not run anywhere near idle speed. It's also possible to mix the slides up between the right and left side carbs. That might be your issue.
     
    gggGary likes this.
  4. grizld1

    grizld1 Grumpy old man Top Contributor

  5. Graeme1198

    Graeme1198 XS650 Enthusiast

    The idle isn’t racing, I’ll check that tomorrow when I get back in the garage. I’ve only had the carbs apart individually so it shouldn’t be but who knows!
    thanks for the input!
     
  6. Graeme1198

    Graeme1198 XS650 Enthusiast

    Thanks for the reply but the link above doesn’t work for me I’m afraid.
     
  7. grizld1

    grizld1 Grumpy old man Top Contributor

    Don't know why the link didn't work for you, I just tried it and it worked fine. Try typing in the address. For some reason I couldn't continue the post above without new script being added to the link, so here's a bit more. Slides must be installed with the arch (cutaway) facing the rear; and yes, in VM34s it is indeed possible to install them backward. Can't help further without a complete jet list, and that means all of the brass. Good luck.
     
  8. Graeme1198

    Graeme1198 XS650 Enthusiast

    Thanks I’ll try to get it to work, I’m going to have a slow go through the jetting and see how I get on!
     
  9. Graeme1198

    Graeme1198 XS650 Enthusiast

    Thanks for all your advise, got the bike running was the slides in the wrong sides.... :umm:

    Running very well now, but the battery now isn’t charging and the headlight isn’t working.....one thing after the other.... means I can spend more time in the garage though :cheers:.
     
  10. 5twins

    5twins XS650 Guru Top Contributor

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    If you have a '78 or later model then those two issues go hand in hand. There is an auto-on headlight relay triggered by a voltage signal from the alternator once the bike is running and putting out a charge. No charging means no signal to the relay. The relay isn't activated and the headlight doesn't come on.
     
    grizld1 likes this.
  11. Graeme1198

    Graeme1198 XS650 Enthusiast

    Yeah I’ve been told this, strange that it was working yesterday.

    Had a look through all the grounds today and The slap test on my rotor is very poor even though the ohms are over 5.
    Tried the green wire to ground on the rectifier and that didn't change the battery voltage....
    does the rectifier ground to the frame where it’s bolted do you know? That’s the only part I’ve not pulled off yet.
     
  12. 5twins

    5twins XS650 Guru Top Contributor

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    It seems you're mixing up your terminology a bit here. These bikes have both a regulator AND a rectifier. On the '79 and older models, these are two separate components. On the '80 and newer models, they are combined into a single unit. But, none of them ground through their mounts. All have a dedicated ground wire run into them.

    The regulator is what controls or regulates the charging output. The green wire to ground test is for it but only valid for the '80 and later unit. Also, when doing the test, you would want to rev the bike up. Checking it just at idle may show little, if any, change.
     
  13. Graeme1198

    Graeme1198 XS650 Enthusiast

    Sorry yes it’s a 82 so the reg/rec is one piece.
    Yeah I tried the green wire with revs also but no ride in voltage.
    I’m going to check the output from the stator next I guess.
     
    gggGary and grizld1 like this.
  14. grizld1

    grizld1 Grumpy old man Top Contributor

    Click the Tech button, scroll down to "Electrical," then scroll down to "How-to: Diagnose charging system problems." Gary did a fine and patient job of explaining the early and late charging systems, how they work, and how to hunt the gremlins that infest them. Thanks to plenty of personal problems posted in a reference thread it's a bit of a slog to get through it all, but the effort will be rewarded.
     
    gggGary likes this.
  15. Graeme1198

    Graeme1198 XS650 Enthusiast

    Shall do thanks!
     
  16. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Like Griz sez http://www.xs650.com/threads/10561
    Couple basics;
    check fuse box, fuses if you are still on the original, the fuse holders tend to rot.
    You need a solid 12 volts on the OTHER brush when the ignition is on.
    Have you checked or replaced the brushes? are they properly installed? They are wear items and install kinda weird with the wire wrapping around the little rectangular plate.
    Carefully check the wire bundle where it passes near the sprocket, worn frayed nicked wires are common there.

    Hey Griz I didn't list THAT many personal problems... ;)
     
  17. Graeme1198

    Graeme1198 XS650 Enthusiast

    I’ve had a good look through the wiring in the fuse box, and everything is in very good condition.
    12 bolts going to one brush.
    Brushes are new and I’ve checked the installation a few times and they look correct.
    Not checked the wire bundle next to the sprocket, I’ll have a good look at that.
    When I try the slap method with the feeler gauge and turn the ignition on. The gauge barley moves unless it’s very close to the nut that holds the rotor on.
    I’ll go through the list and tick everything off and see where I end up!
    :umm:
     
  18. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    Yeah that sounds weak a thin feeler gauge will move even with the "YAMAHA" round cover on the bike.
    Some feelers MIGHT be non magnetic stainless??? hang a combo wrench from a screw driver move it close, is a test method also.
     
  19. Graeme1198

    Graeme1198 XS650 Enthusiast

    I have to take the cover off and if I’m 3-4mm away from the nut it’ll start to wobble and then stick.
    Does this with the ignition on and off regardless.

    Double checked rotor and the ohms are 5.4 after deducting the meters own contact touch and infinity when grounded.
    Strange that it was working yesterday then has just all of a sudden stopped.
    I’ll keep going through the above page and see where I get. If I find my solution I’ll post it and add it to the list of electrical problems!
     

    Attached Files:

  20. 5twins

    5twins XS650 Guru Top Contributor

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    Rotor does seem to be testing OK. Are the slip rings clean? Very dirty ones can hamper output. The points of your meter probes may be getting through the dirt but maybe the brushes aren't.
     

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