Z50 clutch rebuild advice - Page 2

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Z50 clutch rebuild advice

This is a discussion on Z50 clutch rebuild advice within the Z50, CT70 and JDM Monkeybikes forums, part of the General Talk category; Great, thanks!...

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  1. #16
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    Great, thanks!

  2. #17
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    More advice needed...

    So the clutch is rebuilt and works great when kicking now...it never slips, but it won't start. I have checked the points and the spark is good, there is plenty of fuel and the carb is clean...and compression is actually up marginally to 105 psi now. Here are the symptoms when I kick it:

    -Occasional backfires (never did this before)
    -Engine spins more freely with the throttle fully closed than wide open (not sure if this matters, but I'm pretty sure it did not do this before either)

    2 questions:

    1. Is there something I could have screwed up with the clutch repair? I swear I just took off the clutch, replaced the fiber plates and put it all back together.
    2. Is there a certain orientation the flywheel must be re-installed on the crank? My flywheel is attached to the crank with a home remedy fix consisting of a bolt and a drilled crank (see pics), so I can pretty much bolt it on regardless of the valve position, which is confusing to me.

    Any advice appreciated.

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  3. #18
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    With your crank repair, you still have keyways in the crank, and in the flywheel, right? And you should have a key in there to line them up correctly..? So your valve timing should be able to be set properly.

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  5. #19
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    Yes the keyways are there, and it feels like the compression is right as you spin it up to the F and T mark, but I have to check again tonight if there is a way to install it in the wrong positioin.

    Any idea on the backfires and what could be the cause? Thanks...

  6. #20
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    I'm not very good at diagnosing that sort of thing, but I would think carb issue. And going by your previous posts in other threads...You're way rich...Too much fuel. You need to lean it out and buy some more spark plugs. Try lowering the needle that is in the slide...End of the throttle cable. Raising the clip to the top notch will lower the needle to full lean. Start there.
    Then, figure out where your air/fuel screw is set...Turn it in, clockwise, until it bottoms out lightly as you count the turns...Then write it down for reference...Should be around 1½ turns or so (usually) then you can play with that some as you try to make your bike run. Try turning it out to 2½ turns...This should lean out the idle.
    You're fouling out plugs...They're getting all black and fuzzy and then your bike won't run...Right?
    Do something to tune towards lean...Install a new plug, get it running, then tune the carb to run RIGHT. BEFORE you foul the plug again, or overheat the motor, or whatever. Make it run, then make it run RIGHT, only then should you ride it.

  7. #21
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    So the keyways are there on the flywheel and crank, but there is no key so it was way off. I reinstalled the flywheel by eyeballing it and it started up on the 2nd kick. (and this whole kicking without slipping thing is awesome!)

    I have moved the clip up on the needle and will work on the tuning this weekend based on your advice...more help requests will be on the way! Thanks.

  8. #22
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    The missing key may have been the problem all along.

  9. #23
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    OK, here is the latest:

    1. Moved the clip all the way up on the needle and tried to adjust carb as per your instructions. (got it to idle ok...a little high but ok)
    2. The first 1/4 turn is pretty good if you twist slowly, but if you open it all the way up it bogs down. Air screw is out about 3 turns.
    3. It also idles randomly (sometimes ok, sometimes real high, sometimes just dies), and does not always rev back down once you close the throttle
    4. And finally, I guess I need to adjust the sensitivity of the clutch cuz it wheelies when you put it in 1st.

    Any and all advice on how to work through these items is appreciated. Thanks.

  10. #24
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    It's REALLY difficult to try to diagnose and tune a carb from long distance. Hard enough (for me) when I'm right in front of it. First thing...the inconsistent idle, AND the...slow to idle down...sounds like you have a intake leak. Do you have gaskets/o-rings between every single connection?? No stripped threads??? everything is tight and you didn't notice anywhere that may not have sealed up between the carb and the head??

  11. #25
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    Looks like one of the bolts for the carb intake assembly going into the head is striped and spins, so time for a repair. Any suggestions on a helicoil kit? Or other options? Thanks.

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    The M6 X 1.0 heli-coil kit will work for you
    - dirtbkr188 -



  13. #27
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    Thanks!

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