how to setup and fit a 25mm carb

Discussion in 'Maxiscooter Tuning' started by WOLFFY, Dec 3, 2008.

  1. WOLFFY

    WOLFFY New Member

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    4,135
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    Runner 172
    Just looked through the 6 pages and cant find a thing.

    I have fitted my 25mm carb.
    I started turning it over for a lil bit on the electric start to let fuel go into the float.
    It then started for a second then cut out. Turned it over for about 5-7 seconds and it started then cut out again, now it is just turning over and not firing.
    Could any one help me please?
     
  2. kyle1b1

    kyle1b1 New Member

    Messages:
    5,191
    vacuum ?

    adjusted idle mix ?
     
  3. WOLFFY

    WOLFFY New Member

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    4,135
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    Runner 172
    I thought it might of been the vacuum.
    Either side of the carb there is like a "nipple" which looks like a pipe should connect to.
    3 pipes 4 nipples...
    petrol and oil was prety obvious so was left with these other two. But the are directly opposite each other at the top of the carb as if they both lead into the same part of the carb??
     
  4. fatboy87

    fatboy87 Member

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    469
    have a look at the jets m8 make sure theres no muk in the way
     
  5. kyle1b1

    kyle1b1 New Member

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    5,191
    both opposite facing down ?

    will be overflow
     
  6. WOLFFY

    WOLFFY New Member

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    4,135
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    Runner 172
    Me show you.

    [​IMG]
     
  7. WOLFFY

    WOLFFY New Member

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  8. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    et2 monster
    looks like a premix carb.... put the fuel pipe on, put a pipe splitter to the vacumm UNDER the reedblock on the engine casing (where the pump runs into) then plumb the vac into that.. as for the oil.. can ether drill for an oil feed or run premix..

    the silver ones are all overflows (bar the vac).. thevac is the big silver one on the front of the carb (not there) and oil are gold colourd and missing from the look of the pic. hence premix carb (simply 2 holes not drilled into it)

    its not hard really,
     
  9. kyle1b1

    kyle1b1 New Member

    Messages:
    5,191
    the one you put wtf on is petrol LOLOL

    2 each side facing down is over flow the one you names oil is oil and one you named petrol is vacuum
     
  10. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    et2 monster
    okok, just a shit pic...

    BIG black one is fuel, lil gol;d one is oil, big gold one is vac... the others are overflows.. if you need to be told this you REALLY shouldent be changing a carb yourself... wind the idle mix screw all the way in then back out 1 and a half.. will be slightly rich (depending on the smaller jet size) but safe... needle top position
     
  11. WOLFFY

    WOLFFY New Member

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    4,135
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    Runner 172
    Thanks for the help.
     
  12. fatboy87

    fatboy87 Member

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    469
    kyle1b1 true so true :cool:
     
  13. kyle1b1

    kyle1b1 New Member

    Messages:
    5,191
    put the bike in the shed and just go watch teletubbies :w00t:

    you minge.

    anyways have fun :cool:
     
  14. fatboy87

    fatboy87 Member

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    469
  15. WOLFFY

    WOLFFY New Member

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    4,135
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    Runner 172
    Cheers tom, minor an kyle.

    Got it going lolololol.
    So just to clarify because I don't wanna be ruining any 172's.
    Minor said it looked like premix, but in 2nd post said that there was a oil feed.
    So is it a premix?

    Sounds well beefy :cool:
    Run it for like 5 seconds an was like fuck is it premix?
     
  16. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    et2 monster
    right idea, wrong engine... if you follow a 4t guide you WILL run lean and kill your engine... shouldent go by plug till your close enough to be unsure. should be going by sound/responce and feel... use the ancient kiddy guide i wrote.. will have you nice an close anyway... 25's on 172's are easy tho, jetting is really passive (unlike a 70) doesent have to be spot on.. just close enough wich most people will tell you on here.. so 1 and a half turns out, nedle at top/second notch, around a 102 main.. will run, work as it should, if not rollers are wrong, reset them then lean the main out
     
  17. kyle1b1

    kyle1b1 New Member

    Messages:
    5,191
    no it aint premix.

    do what we said so far and all will be good.

    so to claify

    the black one you amed wtf is petrol
    the one you named oil is oil so put the oil line on their
    the one you named petrol is vacuum put the vacuum pipe on their
    the two facing down are over leave them

    as long as you done that all is good in da hood :cool:
     
  18. fatboy87

    fatboy87 Member

    Messages:
    469
    MiNoR cOnFuSiOn iv allway gone by the plug m8 my m8 matt at m+m tuning done it like that and there engines were mad fast. i jest evey one has there on way

    just tringing to help :punk:
     
  19. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    ye nah i get ya m8, and good for helpin as always... but a plug reading is only any good for full throttle.. if its lean as fuck at full throttle and rich as hell at idle its gonna read as a well setup bike... the only way to properly do a plug chop is to get it close.. then take it for a rag with a fresh plug.. turn it off holding full throttle then look for a small ring at the base of the electrode.. this should be chocolate brown (rich on a 4t but perfect on a 2t as its ment to burn oil obv) you should ALWAYS set the carb up by ear THEN go to the plug to clarify your findings.. wich is what m&m do, same as most tunners...

    ether way you c\go by plug AFTER you think its right.. then ajust accordingly. theres no way in hell you can set up needle position main and idle mix from an old plug youv4e run for 5 mins wiht a new carb
     
  20. fatboy87

    fatboy87 Member

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