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First Cafe Racer Mod! 1983 XJ750 Maxim

Discussion in 'XJ Modifications' started by May_J_Aaron, Jun 24, 2018.

  1. May_J_Aaron

    May_J_Aaron Josh May

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    Bike is acting weird.
    I started it up and let it for a few minutes and then shut it off with the key.
    Came back 30 minutes later to turn it on so I can start some synchronizing and all I heard was a click...:(

    Battery has been on a tender and well maintained.

    Fuses are good.

    Gauge acts unusual sometimes when turning the key on, sometimes it lights up, sometimes it doesn’t, also headlight acts a little weird with flickering and sometimes not coming on, oil light only shows when I have the kill switch set to off, nothing happens when I push START, sometimes I get a click near the battery area but can’t find it since it’s a bit random.

    I suspect the Rectifier, how do I test it?
    5720232B-89B0-451D-9640-0048B4906D0F.jpeg

    Should I be looking at something else?

    a 650 diagram appears more accurate than my 750 wiring diagram
     
  2. hogfiddles

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

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    Sounds like a fusebox issue
     
  3. May_J_Aaron

    May_J_Aaron Josh May

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    Checked the fuses and they’re good, none of them popped, and it ran for about 3 minutes straight, turned it off since it starting gradually revving higher and higher as it warmed up even though I tried to turn down the idle speed.

    I can change the fuses just to be 100% sure, they’re cheap and it’ll rule out the possibility of funky fuses.

    I was going to do the carb tune and colortune today....
     
  4. Polock

    Polock Well-Known Member

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    jump the solenoid
     
  5. May_J_Aaron

    May_J_Aaron Josh May

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    Hope I did it right, hard to see how people were doing it on YouTube, it didn’t click it do anything so that means it’s busted?
    6A5201C8-CF0D-45D0-ADE7-D5E90554AE8A.jpeg
     
  6. Polock

    Polock Well-Known Member

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    Franz and May_J_Aaron like this.
  7. May_J_Aaron

    May_J_Aaron Josh May

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    @Polock Oh! That’s so much easier than how people explain it on YouTube! I did it with a screwdriver and there was just a click...
    So that tells me the solenoid is dead!!

    I also tried to bypass the solenoid, hopefully I got this right by connecting the battery positive to the only bolt on the starter using a jumper cable, still only got a click from one of the diode boxes.
    image.jpg

    I heard the “Boing” of a spring within the solenoid.
    Also noticed a very faint sound from the coils like they were charging up “weeeeeep”, it was hard to notice even though I have really good hearing.
     
  8. Polock

    Polock Well-Known Member

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    that says your starter is broke
    put it all back together and start from the beginning, charge the battery and right now think about the starter
     
  9. May_J_Aaron

    May_J_Aaron Josh May

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    So I was right when I turned the key on and connected the battery positive terminal to the starter it should have kicked over?
    I’m gonna pull the starter and see it it works when removed
     
  10. May_J_Aaron

    May_J_Aaron Josh May

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    Ugh! I tore the starter part and everything met spec per Chacals posting on XJ4Ever but it still won’t work :( even check for bolt wiring to make sure it wasn’t touching the body and shorting out.

    If anyone is bored, regreasing the starter gears is probably a good idea, they were sticky and didn’t run as smooth as they could be!
    CEA2015F-AE68-454A-8676-16EE3C97883B.jpeg 1CF74897-EAD9-4855-88F8-FE0D75FECC2D.jpeg 28124B61-648A-4C1F-9EB5-881145237FA7.jpeg
    Looks like I’m putting in another order with @chacal
     
  11. Calvert

    Calvert New Member

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    I think your earlier assumption of regulator/rectifier might be correct. In my experience, when the solenoid clicks but the starter doesn't spin, your battery voltage is too low. Depending on your specific model, one of the wires on the reg/rec (brown on 82 xj650) is looking for voltage to provide appropriate charge. This wire MUST go through a switched connection otherwise it will be a parasitic drain on your system.
     
  12. Minimutly

    Minimutly Well-Known Member

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    This might be correct, but that's a big assumption to make. And Aaron, how did you get to "my solenoid is faulty"?
    You just shorted it out and your starter didnt spin! That means either your starter is duff, or your battery is duff, or the connections from batter to earth, or battery to solenoid, or finally, maybe solenoid to starter are bad.
    Charge and check battery, check batter high current connections, short solenoid (if it doesn't pull in). Starter should spin over. I wonder if your battery was low all the time, and the solenoid stuck on (does happen), further draining the battery (sometimes setting the bike alight too).
     
  13. May_J_Aaron

    May_J_Aaron Josh May

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    I’ve taken care of the battery by using a smart tender that shuts off when done, when testing it looks good too.
    I tried jumping the solenoid and nothing happened so I replaced it.
    I also tried jumping the starter and again nothing happened, this was all right after firing it up but granted I was holding the START button for around 10 seconds to get that initial spark.
    I did take the starter apart and check all the specs and it appeared to look fine, but since it wouldn’t spin I ended up buying a new one from @chacal.
    I’m hoping I just burned it out by holding it too long since I didnt make any significant changes to the wiring especially that have to do with its ability to start.
     
  14. Minimutly

    Minimutly Well-Known Member

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  15. May_J_Aaron

    May_J_Aaron Josh May

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    I jumped the solenoid as recommended after it had the issues by placing a screwdriver onto both bolts of the solenoid.

    my battery looks strong and connect med negative to the body and positive to the bolt.

    I hope there’s no more surprises!
     
  16. Polock

    Polock Well-Known Member

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    ha ha ha, that was a good one :)
     
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  17. May_J_Aaron

    May_J_Aaron Josh May

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    Having issues with syncing carbs now...
    Hogfiddles rebuilt my carbs so I know they’re good but when I have my Carbtune Pro setup as instructed and I try dialing in the screws, no matter what I do it starts revving up to 5-6ooo RPM’s! :mad:

    I can’t even tell what tightening or Loosening the mixture screws do or even the idle screw... :(
    Can someone clarify what the direction of turning screw and idle mixture does to the bike, manual doesn’t explain that simple piece

    I have to keep turning off the bike to prevent engine damage.

    what should I be inspecting???

    •New intake boots on both ends of carb, new valve cover gaskets and rubber bolt things
    •Shims inspected and replaced

    Variables:
    •It’s on center stand
    •Stock headers, no muffler (eventually Mac 4-1)
    •K&N stock air filter replacement, big one from Chacal
    •#124 main fuel jets and #43 pilot fuel jets
    • live in Chandler, AZ elevation = 1214
    2E8385EA-B3EE-4035-AE57-0E39996E2546.jpeg
     
  18. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Turning the mixture screws IN leans the fuel mixture.

    The idle SPEED knob needs to be backed out almost fully.

    Choke is off, correct? Choke plungers closed?

    Throttle cable isn't hung up on the cylinder head, preventing throttle from closing all the way?

    Is it "instantaneous" 5-6K rpm's or it just builds and builds and "runs away" and so you finally shut it down?
     
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  19. May_J_Aaron

    May_J_Aaron Josh May

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    Turning the mixture screws IN leans the fuel mixture.
    -Now I know!

    The idle SPEED knob needs to be backed out almost fully.

    Choke is off, correct? Choke plungers closed?
    -Yes it’s off, barely needed it to start.

    Throttle cable isn't hung up on the cylinder head, preventing throttle from closing all the way?
    -It’s actually quite loose.

    it just builds and builds and "runs away" and so you finally shut it down?
    -That’s exactly what it’s doing!
     
  20. Huntchuks

    Huntchuks Well-Known Member

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    Building RPM's usually happen when warming up the engine with some enrichment (choke). As the engine warms and the RPM's climb you would normally adjust the lever to bring them back down. If you are not using any enrichment lever you might want to double check the plungers.
     
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