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The morning warm up

Discussion in 'Bling and Appearance' at netrider.net.au started by bragi0, May 2, 2006.

  1. Let me preface this question with the comment: I hate carbs. They suck. There is no reason for a motor to have carbs in this day and age. Now that I have that off my chest...

    When I start my ZZ-R250 in the morning it's a little bit tricky. Full choke, blip the throttle. Hit the starter. Drop the choke to 2/3 as it kicks, modulate the throttle to attempt to keep it running. Until it starts to get a little warm it simply won't run at under 3000 RPM. When it hits the first mark on the temp gauge, drop the choke off entirely, modulate the throttle, keep it at 3000 RPM. When it hits the third mark it'll usually be ok to slowly move down to 900-1000 RPM and let it idle... but sometimes it'll stall. Then it's full choke, blip, start, no choke, modulate, 3000 RPM hold, let it warm some more. Wash, rinse, repeat. Gah! Once it's actually warmed up it'll happily idle at 1500RPM.

    Is this normal behavior? Is there anything I can do to change it/improve it?

    I need to start investigating putting megasquirt on the thing I think. *grrr*
  2. Hi bragi0,

    I can't tell you how to improve this, but I can tell you that my ZZR starts with just a press of the starter.

    Now that said, it hasn't been a completely freezing frosty morning yet and it lives happily in the shed, but I haven't used the choke at all and it hasn't stalled when starting (or any other time).

  3. bragi0 - nothing wrong with carbs, especially when they don't have the damned hunting problems of EFI systems and are easy to fix problems with.

    Yours sounds like it needs some maintenance - valve clearance check, balance and possibly blocked idle jets
  4. bragi0 - nothing wrong with carbs, especially when they don't have the damned hunting problems of EFI systems and are easy to fix problems with.

    Yours sounds like it needs some maintenance - valve clearance check, balance and possibly blocked idle jets.

    PS, are the plugs correct range and not too old?
  5. My routine on a cold morning is choke on or mostly on, hit the starter and off it goes. Sometimes it might need just a little bit of throttle to get it going, but as soon as it's running the throttle can come off, and the choke can be backed off until the revs are about 3000. Given a few minutes to warm up, the choke goes off entirely. Unsuprisingly, it won't idle when it's cold without a bit of choke.
    I had a bit of trouble with the bike not idleing at all, but new plugs fixed that. The old ones were filthy, I think some dirty fuel may have been to blame.
  6. yep like other when i had the baby z last winter, about three-quarter choke, hit the start button, wait maybe 30-40secs drop it back to half, go in get gear on (approx. 5mins.) turn choke off and sweet as.

    Sounds like you may need to get it cleaned out
  7. Hi bragi0

    Mine is in the cold of the hills and this is my start routine.
    Choke fully on. No throttle. hit the start button , jump straight on to the choke and move it back to keep the revs at 2 on cold mornings or around 1.5 if not so cold .
    Attach bag to rack.
    Jump back on to the choke cause its now revving again , up to 3 and moving more , adjust choke so reves go back to 1.5.
    Used to go outside and have smoke but dont smoke now , so go and talk to the horses instead , explaining to them why I miss smoking....
    Go back and move the coke back to off. Revs sitting now at just on or teensy bit above 1.
    From go to wo about 4 minutes.
  8. bragi0 things don’t sound right the way you have to warm up your bike, long bursts of choke will foul your plugs, you should get it checked out, sure when you first start a cold motor a richer air/fuel mixture is needed because cold fuel vaporizes slowly. The "choke" at the top of the carburettor provides the richer mixture by closing and "choking off" the carburettor’s air supply.

    Sounds like you have made a small problem bigger by using the choke for too long, ideal way to start up is > engage choke > start engine > at around 30sec choke off whilst opening throttle for fast idle > let fast idle for 1-2 min > ride off.
    Maybe time for a tune up, and an inspection of your carburettor & the choke itself.
  9. Thanks guys. I'll have to take it in to get it checked out, I'm just not a dab hand at carbies.

    EFI I love... I've put it on everything from 1970s VW Passats to 1950s Massey Fergussen tractors :) Hunting? Sounds like someone didn't know how to construct a proper negative feedback loop, or hysteresus. It's amazing how simple EFI can be, and just how much more reliably it can be made to work than carbs. You just need someone with a bit of sense when they're coding the damn controller! That and it's easy to make them spit out handy dandy debug info.
  10. most would say the same about carbies :LOL: :grin: :wink: like anything i guess get someone who knows what they are doing and everything is works like it should.... get joe loser (hope we don't have a member called joe loser :p ) and things never run.
  11. bmw have been making fuel injection systems for more than 50 years (along with their associated suppliers bosch etc) and nearly all the big bikes now, even after many generations still have surging issues - it can't be as simple as you are pointing out when you get surging on:

    all bmw K and R series EFI bikes, Honda ST and CBR series, Yamaha FJR and XJR series.

    If you can solve the EFI problems for all of these manufacturers i'm sure they'd love to swing you a dollar or a job for it.

    EFI was introduced for emissions on bikes, not for performance reasons
  12. having also loved, nurtured and cherished this particular ZZR i can add my tuppenceworth to say that only on cold mornings when it hadn't been started for a while (ie few weeks) did i need to use the choke and even then only for a few minutes.

    Except when the battery started to die - then it required a whole lotta luvin and rollin to get it going. but no probs since the new battery :grin: