Paging the engine experts

Discussion in 'UK Motorcycles' started by Daz, Oct 14, 2003.

  1. Daz

    Daz Guest

    I've just been and started the race bike after about a month of not
    starting it. It was a bitch to get started and once it fired into
    life it was popping through the exhaust. Not popping like you get on
    overrun with a race can but proper hollow popping [1]. It's had
    regular oil changes since I got it but pretty much nothing else. It's
    always run fine but at my last race it was popping quite a bit as I
    rolled through the paddock at the end of a race. It also sounded like
    it was only running on three cylinders when it first started just but
    seemed OK after a few minutes.

    I'm hoping to sell it soon so where should I start looking? Plugs,
    leads? Could the petrol have gone off a bit, although that wouldn't
    explain the problem at the track?

    [1] That probably makes no sense at all

    --
    Daz
    GSXR1000K2 - Fun
    Fazer600 - Purpose
    CBR600 - Racer
    MRO#26 | FOT#115 | FOF#48 | two#41
    http://www.highsideuk.com
    ukrm at btopenworld dot com
     
    Daz, Oct 14, 2003
    #1
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  2. Daz

    mups Guest

    Plugs would be the first place I'd look. Petrol should last a good 6 months
    before it start to go off.
     
    mups, Oct 14, 2003
    #2
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  3. Daz

    Champ Guest

    Not much :)

    Difficult one. First place to start is plugs, and then carbs. It
    won't be the petrol. Our bike became much harder to start at the last
    race, and I suspect that that plugs are on their way out.
     
    Champ, Oct 14, 2003
    #3
  4. Daz

    Daz Guest

    You and mups have said exactly what I thought so at least I'll be
    starting in the right direction. No idea where I'll end up though!

    Ta.

    --
    Daz
    GSXR1000K2 - Fun
    Fazer600 - Purpose
    CBR600 - Racer
    MRO#26 | FOT#115 | FOF#48 | two#41
    http://www.highsideuk.com
    ukrm at btopenworld dot com
     
    Daz, Oct 14, 2003
    #4
  5. Daz

    Robbo Guest

    I've just been and started the race bike after about a month of not
    <Snip rest>

    Prolly a sticky valve thats cleared itself after not being used for a while.
    If it runs fine after this episode and continues to run OK then don't worry


    --
    -
    -

    Robbo
    1500GL 1988 Goldwing (Rebuild in process)
    BotaFOF #19
    E.O.S.M 2001/2002/2003
    B.O.S.M 2003
    FURSWB#1 KotL
    YTC449
    PM#7

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    Robbo, Oct 14, 2003
    #5
  6. Daz

    Champ Guest

    eh? Would you care to explain this? Are you suggesting that a valve
    stayed 'stuck' shut despite a fucking cam lobe whizzing round and
    clouting it many times a second? Or perhaps that it stayed stuck
    open, and somehow missed the piston that accelerated towards it at a
    significant number of metres per second?

    Either you know bugger all about engines, or you can't use the english
    language.

    Or both.
     
    Champ, Oct 14, 2003
    #6
  7. Daz

    Cane Guest

    <fx: strokes chin> Tricky....
     
    Cane, Oct 14, 2003
    #7
  8. Daz

    Ginge Guest

    If he's wearing clown shoes he might just be a clown
     
    Ginge, Oct 14, 2003
    #8
  9. Daz

    Cane Guest

    Cane, Oct 14, 2003
    #9
  10. Daz

    Lozzo Guest

    mups wibbled incoherently...
    The fuel in my CB had been sitting there for at least 5 months. I fitted
    a replacement engine, and the bike fired up on the 2nd kick. I ran the
    bike until it was emptied of fuel with no problems.

    --
    Lozzo
    ZZR1100D, GPZ500S, CBCBCB750RSRSRS
    BOTAFOT#57/70a, BOTAFOF#57, two#49, MIB#22, TCP#7, BONY#9,
    ANORAK#9, DIAABTCOD#14, UKRMT5BB, IBW#013, MIRTTH#15a/16,
    BotToS#8, GP#2, SBS#10, SH#3, DFV#14, KoBV#3.
    Url for ukrm newbies : http://www.ukrm.net/faq/ukrmscbt.html
    www.mjkleathers.com
     
    Lozzo, Oct 14, 2003
    #10
  11. Daz

    Lozzo Guest

    Champ wibbled incoherently...
    You might like to know that some valves do stick just slightly in their
    guides, causing a lack of compression, without pistons hitting them.
    However, you do usually get some warning signs, such as a sound like a
    badly adjusted tappet, and loss of performance.

    --
    Lozzo
    ZZR1100D, GPZ500S, CBCBCB750RSRSRS
    BOTAFOT#57/70a, BOTAFOF#57, two#49, MIB#22, TCP#7, BONY#9,
    ANORAK#9, DIAABTCOD#14, UKRMT5BB, IBW#013, MIRTTH#15a/16,
    BotToS#8, GP#2, SBS#10, SH#3, DFV#14, KoBV#3.
    Url for ukrm newbies : http://www.ukrm.net/faq/ukrmscbt.html
    www.mjkleathers.com
     
    Lozzo, Oct 14, 2003
    #11
  12. Paul Corfield, Oct 14, 2003
    #12
  13. Veggie Meldrew, Oct 14, 2003
    #13
  14. Veggie Meldrew, Oct 14, 2003
    #14
  15. MOREBOLLOXPROBABLY:
    EEErrmmm. Well sometimes, just sometimes mind ewe you just might get a
    bit of rust or summit on the valve face stopping the valve from closing
    to form a 100% gas tight joint. But as this is probably only experienced
    on side valve mowers it has no significance to this conversation
    whatsoeverlike.

    OBNOTBOLLOX:
    Check the plugs, and make sure the exhaust isn't blowing or leaking air.
    Also make sure you han't blown any vacuum takoff plugs out from the
    carbs or inlets. That's a favourite...




    --
    SimonB - South Wales. BOF#32
    *******************************
    Triumph Sprint ST,
    ZXR750L2 Wazimbaki.
    Kawasaki Z1R For Sale
    *******************************
     
    eric the brave, Oct 14, 2003
    #15
  16. Daz

    petrolcan Guest

    *glum wave*
     
    petrolcan, Oct 14, 2003
    #16
  17. Daz

    sweller Guest

    What he says.

    In your case, however, I'd start at the plugs. 90% of the time misfires
    are ignition related.
     
    sweller, Oct 15, 2003
    #17
  18. Daz

    sweller Guest

    Oooh, good point.

    <vaguely related>
    I had a VW camper that wouldn't idle (ran OK under load though) after a
    bit of enthusiastic air line action. Found the tiny little airway
    blanking plate that had been blown off. But only after after much
    painstaking hunting in the engine compartment.
     
    sweller, Oct 15, 2003
    #18
  19. Daz

    christofire Guest

    I thought the general thing was three months. When I was at Marina &
    Owen's, he was trying to get a bike started that had three-ish old month
    petrol in it and wouldn't go. One fresh tank later and off it went.

    Also gives you an excuse to get water pistols, fill them and then shoot
    the barbecue.
     
    christofire, Oct 15, 2003
    #19
  20. Depends on where the petrol is bought from. supermarket stations
    get the older stuff (they have a higher turnover, so it's not
    going off in the pumps as much as a village BP station would)
    so that will go off quicker.

    (this was true a couple of years ago, may not be now.)
     
    William Grainger, Oct 15, 2003
    #20
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