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Help ZXR250 idle issues... (another one)

Discussion in 'Kawasaki 250cc In-line 4's' started by DanoHosko, Dec 7, 2019.

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  1. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Queue the music...

    Issues issues issues

    Firstly, fouled spark plugs, couple times ive cleaned them but they seem to be getting wet and then not sparking
    @TonyZXR has suggested they are too rich already
    Really struggling to get it started now, if i pull out and clean the plugs i can get it to go again, however it really needs a good blast i think.
    (New battery)


    Clutch issue, clutch seems non existent although it has a new cable from motorcyclespareswarehouse
    Can see the clutch basket move and feel it, can't really see any other clutch cable adjustments to make to change it
    Is it possible that cold oil is the issue? Making the clutch sticky, hasnt been warmed up properly in months...
    Either that or the clutch cable is too long but im pretty confident the clutch arm thing is moving its full throw so should be activating..
    Clutch worked when i first bought the bike 6 months
     
    Last edited: Apr 30, 2020
    DanoHosko, Apr 30, 2020
    #61
  2. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    OK, as others have suggested:

    Replace the intake manifolds and clamps. New vacuum lines can't hurt, either.

    Based on your flooding problem I would say replace the fuel valve seat o-rings in the carbs, they split and then leak fuel around the outside, ie the needle/float is no longer in control of the fuel supply.

    Since you have the plugs out, do a compression test. Throttle wide open and slides lifted, or remove the carbs. If readings are low then it's likely the valve clearances need to be done, or the rings are worn out, but doing the valves will always help - it's adding compression back to the engine for the cost of shims, basically.

    Clutch - any movement between the steel back gear and alloy basket means it's junk, they are riveted together and do wear loose over time. Loose springs on the back are common but not the end of the world.

    As for plate stack, the manual is useless. The stack goes - Fibre, thick steel, fibre, thin steel, etc. The steel plates are alternated thick and then thin. Chamfered egde faces in. The fibres are directional and must be fitted as per the manual.

    Battery / charging system. Charge your battery first, it should rest at 12.8v

    As for your ignition system... replace the plugs as a matter of course, once they've fouled a few times, they're junk. Iridiums more so than regular.

    A good upgrade is to replace the old coils and leads with Ninja 300 stick coils. I bought 4 2nd hand coils, some connectors, and made a harness. No more dodgy spark leads or caps to deal with.
     
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    Linkin, Apr 30, 2020
    #62
  3. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Hey mate, cheers for the reply, I'll confirm:

    - intake boots and vacuum lines have been replaced, clamps are tight happy with them
    - carbs have been synced
    - carbs fitted with litetek kit
    - valve clearances have been done
    - fuel tap is new
    - battery is new
    - fuel tank lid left open to rule out breather issues
    - new clutch, throttle and choke cables fitted
    - rocker cover and spark plug seals replaced
    - cam chain replaced and timing set
    - cam chain tensioner reset


    Maybe I'll have to bite the bullet and get the carb rebuild kit then
    As for the clutch, i haven't had the cover off to look if I'm honest, was hoping to avoid it as i don't have a spare gasket at the moment
    Got new ignition leads on the way, hoping to source some new plug caps asap
    Will replace the plugs too, pretty sure they have done less than 100km but i didn't fit them

    The 300 mod is interesting, might put that on the back burner for now though


    :cool:
     
    DanoHosko, Apr 30, 2020
    #63
  4. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    OK if you've done all that then rebuild the carbs for sure. Litetek and Keyster kits will give you all new brass bits and rubber bits.
     
    • Agree Agree x 1
    Linkin, Apr 30, 2020
    #64
  5. TonyZXR

    TonyZXR Well-Known Member

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    Beware , i have had the issue where motorcycle spares warehouse has sent me the wrong cable and blamed it on my bike (lol right) cable was too long and the bend incorrect Screenshot_20200430-190048_Gallery.jpg
     
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    TonyZXR, Apr 30, 2020
    #65
  6. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    Before rebuilding the carbs wouldnt it be a better idea to do a compression test???
    If the rings are stuck or worn sufficiently no matter what you do the thing wont run or at best wont run well.

    Better still... find someone who has a leak down tester and do a leak down test.. that will tell you all you need to know.
     
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    Andych, Apr 30, 2020
    #66
  7. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Yep sounds good to me, I'll probably get a compression/leakdown first as @Andych suggested if its cheaper haha



    Ah mine is the same as the shorter one so thats a good sign :D
     
    DanoHosko, Apr 30, 2020
    #67
  8. ShaneP

    ShaneP Well-Known Member

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    I had issues with a carby overflowing because of wear on the float needle and seat, it would occasionally stick and not shut off. Did you check fuel float level?

    As for the clutch, it is common to have them stick if they have sat for months. You can try putting it in gear, hold the clutch in and try rolling back and forth to free it up. There's a couple of other techniques without opening it, but they are tricky or require equipment.
     
    ShaneP, May 1, 2020
    #68
  9. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Hey mate, i set the floats on the carbs but haven't checked the fuel height as such since then

    Had it running today with choke on to get the oil hot, clutch seems to be working better and coming unstuck so that's a win!


    Its odd though, over the weekend i synced the carbs and she idled perfectly
    Monday discovered headlight relay knackered so fixed that, but since then won't idle anymore without full choke again?

    When i synced i did do it without the airbox on, wondering if that was a mistake?
    But I'm certain i tested with the airbox on after syncing and it was fine

    Mixture screws are at 3 turns at the moment....


    Working Sunday:




    Today, full choke
     
    DanoHosko, May 1, 2020
    #69
  10. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Typical Kawasaki choke, too many revs or it stalls.
     
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    Murdo, May 1, 2020
    #70
  11. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Ok had a win today :cool:
    Got my mate round for a look (kept our 1.5m distance of course)
    I'm chasing air leaks, he found the throttle cable assembly on the handle bar is loose, pin had pushed out :headbang:

    Sorted it out, little twiddle on the idle screw (less of my heavy handedness)
    Running like a dream :drinks:
     
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    DanoHosko, May 1, 2020
    #71
  12. TonyZXR

    TonyZXR Well-Known Member

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    Congrats, now time to ride and find more issues haha

    Sent from my SM-N960F using Tapatalk
     
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    TonyZXR, May 1, 2020
    #72
  13. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Haha yeah, still gonna replace HT leads and plug caps when i have the parts ;)
     
    DanoHosko, May 2, 2020
    #73
  14. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    G'day all!
    I really think I should of made one project thread at the start but hey ho, glad to say she's up and running a registered now. Has been a good project to keep my hands busy during lockdown
    :cool: :imtheking:


    A summary of the work I've done on her:
    - Cam Chain replacement
    - Cam chain tensioner clean and reset
    - Valve clearance shims replaced
    - Litetek carb kits fitted
    - Carbs cleaned
    - Intake carb holders replaced
    - Carbs synchronized
    - Vacuum hoses and fuel line replaced
    - Fuel tap replaced
    - Rocker gasket and spark plug gaskets replaced
    - HT leads and plug caps replaced
    - Water pump impeller, shaft and seals replaced
    - Clutch hub inner & nut/washer replaced (after i broke the inner hub)
    - Clutch, choke & throttle cables replaced
    - new wheel bearings and dust seal
    - new tyres (Pirelli Diablo Rosso 2's)
    - bodged up wiring for dodgy headlight relay
    - new indicator flasher
    - fixed dodgy rectifier wiring
    - new 35/55W headlight bulbs (correct ones)
    - cleaned and painted exhaust pipes
    - brake fluid replaced
    - oil filter and oil changed
    - new coolant

    Hopefully that'll be it for a while, there's a few minor issues and tuning that I need to address but nothing that stop's her running

    - Takes ages to warm up 5 minutes at least (I'm expecting the thermostat could be dodgy)
    - When warming up on idle, you can't put on any throttle until sufficiently warm else it will stutter and try to die (i'd say that's a carburettor quirk?)
    - Revs hang a little when taking off throttle, my mixture screws are set 3-turns out so maybe too rich?
    Guessing the lean/richness of the mixture won't affect how it warms up?
    - front brakes aren't the best but will give them a service soon


    Cheers all for your patience and all the help from various guys over multiple threads :bowdown:
     
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    DanoHosko, Jun 8, 2020
    #74
  15. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Carby bikes take a while to warm up, even on choke. The owner's manual will have choke settings for various temperature ranges. Dying on throttle could be either too rich or too lean, it is hard to diagnose over the internet. It could be excess fuel pooling on the throttle plates, where opening the throttle dumps the liquid fuel into the cylinder and kills it because it can't be burnt. It could also be too lean via air leaks and also totally die when you open the throttle (more air being supplied).

    Mixture screw and idle setting really need to be done as part of a carby balance, but you could try winding them all in 1/2 a turn to start, 3 turns is somewhat rich. 2.5 turns is more in the normal range, but it's anyone's guess as to the optimum setting, especially on old bikes.

    As for your front brakes, a new set of pads to start with, and inspect all the caliper pistons and seals while you're doing the pad replacement.
     
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    Linkin, Jun 8, 2020
    #75
  16. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    @Linkin I'm leaning towards it being too rich so i know i set the mixture slightly richer than standard
    I can't imagine where else there would be any air leaks now as pretty much anything that would allow an air leak i have replaced (i believe)

    Edit: i should of mentioned, if i drop the idle screw a tad the revs dont hang but probably idles too low



    I'll spend this week running in the new tyres then re-assess next week, at the moment apart from those revs hanging at 4k for maybe 5 seconds shes running sweeeeet when warmed up
     
    Last edited: Jun 8, 2020
    DanoHosko, Jun 8, 2020
    #76
  17. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    Check for air leaks with some starting fluid, brake clean or the like. Just a quick squirt around suspected areas like carb boots and vacuum lines.

    If the revs drop low when you adjust the mixture, set the main idle higher. If you can't get a sweet spot then either it needs another balance (which should be done on a cold engine, not hot) or there is some other problem.
     
    Linkin, Jun 8, 2020
    #77
  18. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    Yep will do, vac lines and carb holders are all new so hopefully shouldn't be leaking :D
    I'll give it a spray though for sure
     
    DanoHosko, Jun 8, 2020
    #78
  19. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    I don't know if I mentioned it before, but you cannot use our float seat o-rings on Keyster float seats. Keyster need a thicker o-ring than the OEM part.
    Cheers
    Blair
     
    Last edited: Jun 24, 2022
    maelstrom, Jun 24, 2022
    #79
  20. DanoHosko

    DanoHosko Well-Known Member Premium Member

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    I believe mine are OEM; assuming I would of had issues by now if mine were the Keyster float seats? :crazypilot:
     
    DanoHosko, Jun 25, 2022
    #80
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