Date: 13-06-21  Time: 08:40 am

Author Topic: Rough running FZS1000  (Read 376 times)

BJohnD

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Rough running FZS1000
« on: 13 May 2021, 09:32:42 pm »
I’ve recently bought another FZS1000 and  been trying to get it to run right. It stutters at low revs (up to 3k) and backfires on overrun. It pulls well above 3k but doesn’t feel as powerful as my previous but that maybe because it had an Ivan’s “slip on” kit, which I haven’t yet installed on this one. It’s done 46k
 
I’m looking for ideas on what may be the problem as I’m running out of ideas myself.
 
    • Done so far:
    • Stripped and cleaned carbs
    •    Cleaned jets, checked sizes. Needle size & position
    •    Checked diaphragms for punctures
    •    Checked float height
    •    Balanced Carbs
    • Set valve clearances
    • TPS failed so new TPS, set to 5k (tried 10k bounce)
    • Checked & cleaned electrical connectors
    • New filters (air, fuel & oil)
    • Check resistances etc on Coils, TPS, sender, plug caps
    • Swapped out plug caps to make an equal set
    • Cut recommended ½” from ignition leads
    • Changed plugs (CR9E & CR9EIX)
    • Stripped Exup & straightened to ensure it opened & closed smoothly, rebuilt & adjusted
    Seems to runs best with mixture screws 2½ turns out
    Plugs are whiteish
     
    I haven’t checked the compression yet but don’t see any indication that is the problem.
     
    My next thought is a worn cam chain, anyone any experiences with this or know where I can find timing for valve opening & closing?
     If I replace it, I am assuming I will have to use a “split” chain (at £80) rather than the original endless (at £24), unless anyone can advise a way to do it without splitting the crankcase.
    « Last Edit: 13 May 2021, 09:50:33 pm by BJohnD »

    Falcon 269

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    Re: Rough running FZS1000
    « Reply #1 on: 14 May 2021, 08:24:46 am »
    Cam chain won't be worn at 46k.  I know of Gen 1s with 146k on the motor and still no cam chain wear. :)

    I don't see mention of you changing the O-rings on the float valve needle seats.  That would be my first port of call for any low-speed rough-running issues, along with the pilot jets and their passageways.

    Gaz66

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    Re: Rough running FZS1000
    « Reply #2 on: 14 May 2021, 12:18:39 pm »
    Cam chain won't be worn at 46k.  I know of Gen 1s with 146k on the motor and still no cam chain wear. :)

    I don't see mention of you changing the O-rings on the float valve needle seats.  That would be my first port of call for any low-speed rough-running issues, along with the pilot jets and their passageways.




    Good call Mike, u beat me to it ...
    Sun is out, the sky is Blue, I'm a complete FOCCER & so are you.

    BJohnD

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    Re: Rough running FZS1000
    « Reply #3 on: 14 May 2021, 04:37:38 pm »
    Cam chain won't be worn at 46k.  I know of Gen 1s with 146k on the motor and still no cam chain wear. :)

    I don't see mention of you changing the O-rings on the float valve needle seats.  That would be my first port of call for any low-speed rough-running issues, along with the pilot jets and their passageways.

    I have only found one person who has said their cam chain was worn, hence wanting to find the valve opening & closing angles so that I can check mine to see if the timing is right. If I could use the endless chain, for £24, I’d put one in to make sure, but, at £80 for a split chain, I’d want to be more certain.
     
    I have changed the “o” rings even though there was no sign of flooding. The carbs were my first port of call to clean jets etc. I’ve now stripped and cleaned them 3 times. I think I’ve got the passageways checked, but had hoped to find a fuel & air flow diagram for them so I could be sure I’ve got them all clear where they need to be.
    « Last Edit: 14 May 2021, 04:39:34 pm by BJohnD »

    Gaz66

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    Re: Rough running FZS1000
    « Reply #4 on: 15 May 2021, 09:41:37 pm »
    Exup valve all free & adjusted correctly with a bit of cable free play?
    Check actuator's not seized, crank motor over with kill switch "Off" while watching Exup pulley, pulley should rotate clockwise about am 1/8th of a turn & return back rest position after cranking.


    Back-firing on over-run? I've had this issue with my Kawy ZRX11 ... tiny O-ring missing from carb mixture screw (previous owner) I might add, backfired like a bastid till I found it when I pulled carbs to apart.


    Have u pulled main loom multi-plugs apart to check for bad connection & corrosion? especially plugs in left side fairing.
    I assume you've a good battery? & checked all resistance limits on ignition & charging system, all can make bike run shite.
    Have u fitted Iridium plugs? older ignition systems tend not to like em, probly best to stick to original spec plugs.


    What type of air filter fitted? K&N's make any bike run like a bitch if even slightly over oiled.


    Let us know how you're getting on, all being well the fault will be found?

    Sun is out, the sky is Blue, I'm a complete FOCCER & so are you.

    BJohnD

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    Re: Rough running FZS1000
    « Reply #5 on: 16 May 2021, 10:15:07 am »
    Exup is free and working OK, it was bent and jamming but sorted now and functioning.

    All the washers & o rings are in place in the carbs

    Have checked & cleaned the connector blocks, battery is good (having kept the week old one from my written off bike, I bought a bike with a new one!!)

    Checked all the ignition system resistances (haven’t done any of the charging system)

    Everything is standard and I have replaced the air & fuel filters

    Your comment on Iridium plugs is interesting, I always felt my old Fazer ran better on CR9E, I’ve tried this one with both CR9E & CR9EIX.

    I have just stripped the carbs (4th time now!!) and paying particular attention to the passageways which carb cleaner flows through OK. So I’ll see if that has any effect later
    « Last Edit: 16 May 2021, 10:15:52 am by BJohnD »

    unfazed

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    Re: Rough running FZS1000
    « Reply #6 on: 16 May 2021, 09:24:17 pm »
    since you appear to have ruled most of the obvious things there is one other possibility,  one or more of the much forgotten  Air Cut also called the Accelerator Pump diaphragms has a hole.
    This can give the symptoms you describe poor initial acceleration and backfiring on deceleration on a fully closed throttle.The unfortunate side of checking them is that the one on the left is easy to get at to check but the other 3 need the carbs to be separated to check them.
    The reason behind it is to provide a dash of fuel for quick throttle opening from idle and at closed throttle on deceleration to stop the lean popping in the exhaust .

    It has caught out many a mechanic. I first came across the issue on a Ford Cortina way back in 1979 and a few Hondas and Suzukis since with similar issues. Most fellows replace the carbs without checking it which is why you don't hear much about it.

    Gaz66

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    Re: Rough running FZS1000
    « Reply #7 on: 18 May 2021, 11:46:26 pm »
    since you appear to have ruled most of the obvious things there is one other possibility,  one or more of the much forgotten  Air Cut also called the Accelerator Pump diaphragms has a hole.
    This can give the symptoms you describe poor initial acceleration and backfiring on deceleration on a fully closed throttle.The unfortunate side of checking them is that the one on the left is easy to get at to check but the other 3 need the carbs to be separated to check them.
    The reason behind it is to provide a dash of fuel for quick throttle opening from idle and at closed throttle on deceleration to stop the lean popping in the exhaust .

    It has caught out many a mechanic. I first came across the issue on a Ford Cortina way back in 1979 and a few Hondas and Suzukis since with similar issues. Most fellows replace the carbs without checking it which is why you don't hear much about it.


    I've always ripped out the air injection bollox on any bike I've owned with it fitted, I never mentioned this potential issue, I just assumed the air injection crap had already been removed & smashed with a 4lb hammer like it deserves ... lol :rollin
    « Last Edit: 18 May 2021, 11:51:27 pm by Gaz66 »
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    unfazed

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    Re: Rough running FZS1000
    « Reply #8 on: 20 May 2021, 05:40:23 pm »
    The AIS is a totally different ball game to the system on the side of the carburetors and is needed for smooth running.
    My serow even had an AIS which I also promptly removed, removed the AIS on the 1000 a week after buying it.