carb setup, strange results,

Discussion in 'Maxiscooter Tuning' started by seanwhite06, Sep 21, 2008.

  1. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    right,

    mate of mine has exactly the same setup as mine which is...
    172
    pm59
    28mm dellorto with open filter
    180 variator,

    only difference is i have 13g rollers and he has 12.5,

    the problem im getting trying to set his bike up for him is that his carb seems to be running a extremely large main jet, mines running a 109 and seems nice, his has a 120 in at the mo and you still get that quick/ snapping open throttle bogging out/dieing which i understand is a lean main jet ? :wtf:

    now i no all bikes are different but just seems a bit drastic? any ideas?
     
    seanwhite06, Sep 21, 2008
    #1
  2. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    no thats rolelrs... couls well be an air leek somwhere
     
    MiNoR cOnFuSiOn, Sep 21, 2008
    #2
  3. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    what do you mean by rollers minor?

    could you explain more please,

    acvcording to a carb jetting guide which i followed, which worked perfectly fine for my bike, the quick action snapping of the throtle if it died or struggled to rev then picked up it ment a lean main jet? is this wrong then?

    i thought there could be a air leak also so we reaasembled EVERYTHING! new gaskets throughout, re torqued everything and brought new inlet manifold too but still no luck?
     
    seanwhite06, Sep 21, 2008
    #3
  4. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    quick snapping of the throttle at idle and bogging is idle mix.. at low speeds its clutch and above 20 ish its rollers too heavy.
     
    MiNoR cOnFuSiOn, Sep 21, 2008
    #4
  5. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    right its only from idle,

    i set the idle mix the way ive always been taught.. main jet out, set air mix at all the way in then quarter out, thenhold steady eighth of a throttle and work air mix screw out slowly untill it reaches its highest rpm, then reset the idle speed sscrew.

    with this method it snaps of throttle easily right up untill past 3/4 throttle when the main jet comes into play and then it spluttters.


    wrong way then minor? or am i needing a new pilot jet im now starting to think?
     
    seanwhite06, Sep 21, 2008
    #5
  6. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    big carbs and soft clutch springs dont help.. bang some blues in if there not.. theres many ways to set the idle mix, i prefer the ride and ajust method. just set it with the jet in so it is responcive and the revs drop off if snapping the throttle... if it bogs out atall at higher speeds ajust further..
    the method you use is fine tho just a bit long winded. will be down to the mix rollers an clutch tho. no 2 bikes run the same as you know so experiment. will be supprised what you find if you try things you wouldent think work ;)
     
    MiNoR cOnFuSiOn, Sep 21, 2008
    #6
  7. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    forgot to mention there were blues in there aswell :emb: sorrry

    yea doesnt really bog out at higher speeds at all, so my guess is just the idle mix,
    120+ does seem stupidly big though and you do get that let of slightly and seems to go faster syndrome which is rich yer?
    ill have another play this afternoon and report my findings again later, lol
     
    seanwhite06, Sep 21, 2008
    #7
  8. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    120 is HUGE lean is faster rich is slower.. both run hot
     
    MiNoR cOnFuSiOn, Sep 21, 2008
    #8
  9. seanwhite06

    seanwhite06 New Member

    Messages:
    358
    Rides:
    runner 172, zx6r
    right had a play again today but still no luck, :(

    basically used every jet i have from 100 upto 120, the small jets die strait away on quick wide open throttle openings from idle, the largest jet 120 bogs slightly then revs up cleaning,

    i tried all the jets with the air screw in every single different quarter turn position! :(


    now im totally confused......

    any more ideas you lot? .
     
    seanwhite06, Sep 22, 2008
    #9
  10. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    the main jet isnt quick action.. its plain old full throttle... you want to play with the mix and the needle, if this doesent cure it trim out the pilot jet. deffo check every pipe in and out tne engine for leaks end to end. check the fuel pump has no cracks in it and check the atomiser isnt bunged full of shit. try again, its deffo too big. ajust main at full throttle and idle at idle.. other methods are confusing. slow progression throuought throttle possitions are down to the respective part of the carb. fast snaps are down to idle mix mostly.. somtimes the slide needle profile and atomiser have an effect and RARELY the main jet. trim each thrpottle position out on a constant hold and setup accordingly.
     
    MiNoR cOnFuSiOn, Sep 22, 2008
    #10

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