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1981 XJ 650 unable to set idle

Discussion in 'XJ Technical Chat' started by mal in oz, Feb 27, 2016.

  1. hogfiddles

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

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    Reminds me of another forum I used to be on--- guy was complaining that his brakes kept locking up on the from and nose-dived when braking..... After much discussion, Finally made the comment that his back brakes weren't hooked up yet........DOH--face palm.
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    it should be an automatic posted reply by the site computer when ever the words wont idle comes up
    "Got Pods"?
    he has answered 3 of 4 questions I asked so far.

    question 4 would you answer it

    You say set the float levels do you mean you wet set fuel level or dry set float height?

    your getting fuel if plug is wet
    1 replace the plug
    2 if spark plug cap is a part separate from the wire cut back the lead to ensure that you have a good connection

    3 read this thread it will guide you on jet replacment when you modify stuff. you will have to search for the info as it is packed with different info.

    The Information Overload Hour


    http://xjbikes.wikidot.com/carb-specs
    is this your bike???
    Years & Models: 1980-1 XJ650 4K0 and 4K1 models (UK/Europe)
    Carb Manufacturer: Hitachi
    Carb Series: HSC32
    Carb Model ID: 4K000
    Main FUEL Jet Size: #110
    Pilot FUEL Jet Size: #40
    Main AIR Jet Size: #50
    Pilot AIR Jet Size: #195
    AIR COMPENSATOR Jet Size: unknown
    Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
    Main jet NEEDLE ID: #Y-11
    Main needle JET Size: #3.2mm (the main needle JET is also known as the "power valve" or "emulsion tube").
    Fuel Level in float bowls: 3mm +/- 1mm (.118" +/- .039")
    Idle RPM's: 1,050 rpms

    Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

    Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
    Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")
     
  3. XJ550H

    XJ550H Well-Known Member Premium Member

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    DR my arm keeps hurting when i do this..............
    sounds like an episode from the 3 stooges
     
  4. hogfiddles

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

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    I wouldn't worry about being 70 less. It's more important that it is 'sat-overnight cold'. I've never had issues with shims on an 85 degree day, etc.... But don't check clearances on the same day that the bike was running.

    If any bikes need clearances check at a carb clinic, I insist that the bike be dropped off at least a day in advance. That way I KNOW the bike has sat overnight.
     
  5. mal in oz

    mal in oz New Member

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    Yes the jets are stock, but can the mixture screws be adjusted to compensate? Or what sizes do I need?
     
  6. mal in oz

    mal in oz New Member

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    Thanks for the advice. The carbs are as clean as when they left the factory, and have been wet set and bench synced. The rest of the items you have mentioned I will check again. I told one of the other guys that the bike has K&N pods on it and he seemed to think this would make it very difficult to sort. But I noticed several of the members have bikes with after market exhausts and pods, so what did they do?
     
  7. hogfiddles

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

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    Constantly fiddle and fart around with him and trying get them to where it's the Most acceptable performance. Some are lucky enough to have it dialed in fairly well. Some Keep at it it by trial and error. Some give up and put the airbox and filter back in, go back To the original jetting, Re-tune their bike.... Then go enjoy riding
     
  8. hogfiddles

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

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    Then, of course there are those that, If a plug is not firing properly, will try putting a new spark plug and first…
     
    k-moe and XJ550H like this.
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    just think of it this way, you can look cool with pods or pull up aside of someone who looks cool with the pod set up , rev your bike on leave him behind in your dust because you will not have that flat spot in the throttle response. your bike will just pull hard through out the throttle , giving you that edge
     
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  10. k-moe

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

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    Mostly they put-up with a bike that doesn't perform well.
    Your idle issue (not the faulty plug that you should replace) is directly attributable to the pods. You're running too lean.
     
  11. mal in oz

    mal in oz New Member

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    I think I will put new plugs in and get a colortune, then see where I am at. If the pods will not work I still have the original air box and a new filter, I took them off for two reasons, one I think the pods look better, second it makes taking off the carbs a lot easier.
    Don't know if this is relevant, but when I was checking out the ignition system I found the grey and orange wires that go from the TCI unit to the coils have a resistance of 0.2 ohms. But the red and white wires that go from the TCI to the coils has a resistance of 3.4 ohms. Should there be a difference or do the red and white wires got through a switch or something? Everything else checks out ok.

    If the TCI were faulty what options are there, are there any aftermarket units available in the US, certainly none over here.
     
  12. mal in oz

    mal in oz New Member

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    I think I will put new plugs in and get a colortune, then see where I am at. If the pods will not work I still have the original air box and a new filter, I took them off for two reasons, one I think the pods look better, second it makes taking off the carbs a lot easier.
    Don't know if this is relevant, but when I was checking out the ignition system I found the grey and orange wires that go from the TCI unit to the coils have a resistance of 0.2 ohms. But the red and white wires that go from the TCI to the coils has a resistance of 3.4 ohms. Should there be a difference or do the red and white wires got through a switch or something? Everything else checks out ok.

    If the TCI were faulty what options are there, are there any aftermarket units available in the US, certainly none over here.
     
  13. jayrodoh

    jayrodoh YimYam Premium Member

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    How are you testing? This really won't tell you anything. You have spark on all cylinders, so you shouldn't have a TCI or pickup issue. You can test the coils by getting an Ohm reading across red/white and gray and red/white and orange (unplugged from the TCI of course).
     
    Last edited: Mar 1, 2016
  14. mal in oz

    mal in oz New Member

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    I am using a multimeter set on 200 ohms scale. I checked the wires from the connectors on the TCI box to the connector onto the coil disconnected at both ends, just in case there was a break or short, I know the coils are ok because they are new not sure about the TCI box. Just wondering why there is such a difference between the two wires that go to and from the same place.
     
  15. k-moe

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

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    Becasue they don't go to and from exactly the same place. You have spark on both coils. Your TCI can be assumed to be fine at this point. Work one problem at a time or you'll go crazy and never make any progress.
     
  16. M Chang

    M Chang New Member

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    For rejetting just for future info "jets r us" has our jets
     
  17. k-moe

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

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    So does Chacal.
     
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  18. hogfiddles

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

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    He has NEW PLUGS available, too----

    Have you thought of trying new plugs yet? It could be as simple as that.....
     
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  19. wizard

    wizard Active Member

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    Good starting point with pods is up 2 on the mains & up 1 on the pilots.
     

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