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Carb Synch tutorial question

Discussion in 'Technical Q&A' started by Mr Iceman, Apr 18, 2005.

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  1. Mr Iceman

    Mr Iceman Karting

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    #1 Mr Iceman, Apr 18, 2005
    I have recently been getting quite intimate with my carbs, general inspection and cleaning etc following some of the excellent guide posts on this forum. I am now wanting to check and possibly adjust the synch, I have purchased an airflow meter and have read Birdmans excellent "Carb synch tutorial for 308", However because this was posted before the hard disk meltdown all the pictures have gone.
    I was wondering if anyone had the pics on there hardrive and could repost or email them to me? I am especially interested in pics showing the location of "the air bypass screws" .

    Any help would be appreciated.

    Scotty
     
  2. carl888

    carl888 F1 Veteran
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    #2 carl888, Apr 19, 2005
    Scotty, the pics of the bypass screws are detailed in the workshop manual.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #3 Steve Magnusson, Apr 19, 2005
    Page C20 Fig 19 -- labeled "D - Screws for depression balancing in the carburettor ducts (by-pass)"
     
  4. snj5

    snj5 F1 World Champ

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    #4 snj5, Apr 19, 2005
    Last edited by a moderator: Sep 7, 2017
  5. Mr Iceman

    Mr Iceman Karting

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    #5 Mr Iceman, Apr 19, 2005
    Thanks very much guys, especially nautique who emailed me the original guide with pics. much appreciated.

    I guess I should have figured that "Screws for depression balancing in the carburettor ducts" was Italian technical English for "Air Bypass Screws" !!

    Thanks again
    Scotty
     
  6. Birdman

    Birdman F1 Veteran

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    #6 Birdman, Apr 20, 2005
    I wrote up a more detailed and illustrated version of that tutorial and sent it to Rob. He claims it will be up soon in the new tech section. (STILL waiting Rob! ;)) I'll have to go find those pics and post them again in the thread in the meantime. I didn't realize that they were lost. What a bummer!

    Birdman
     
  7. F308 MAN

    F308 MAN F1 Rookie

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    #7 F308 MAN, Apr 21, 2005
    scott ... i printed birdmans' excellent tutorial prior to the piccy crash .... let me know if you would like a copy in the post, as i have your address.
    cheers, d
     
  8. Mr Iceman

    Mr Iceman Karting

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    #8 Mr Iceman, Apr 21, 2005
    Thanks very much dave, but Nautique emailed me a PDF copy, and Birdman has just reposted the pics on the original thread.

    thanks for the offer though

    Regards
    Scotty
     
  9. F308 MAN

    F308 MAN F1 Rookie

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    #9 F308 MAN, Apr 21, 2005
    no worries, scott .... are you "doing" the valve clearances, as i have spare shims ?
    cheers, d
     
  10. Mr Iceman

    Mr Iceman Karting

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    #10 Mr Iceman, Apr 22, 2005

    Mmmmm, hadn't intended to, How big a job is it? I think I'll leave it be for now, got my hands full with carbs at the moment, thanks for the offer though.


    I'm in the process of checking the float level prior to checking the synch, I was wondering how much tolerance there is in this. the floats are set at the moment from 51mm at best, to 54mm on the worst one, Quite a way off the prescrbed 48mm! what effect would this have on the running? I'm assuming it would mean there was less fuel available in the bowls to supply the jets?

    I'm trying to rectify a flat spot in the power curve that ocurs quite dramatically at about 3000~3500 Rpm. Its always been there , but has become more apparent since I removed the sound absorbing material from the airbox. after I've synched the carbs I plan to experiment with some larger jets (140's) and smaller air correctors (190's).

    I'm hoping to get it finished tomorrow.

    Cheers
    Scotty
     
  11. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #11 Rifledriver, Apr 22, 2005

    Webers are more sensitive to float height than many carbs. Also remember that the key to multiple carb applications where you have a carb feeding a single or a few cylinders as apposed to an American motor where the carbs all dump into the same manifold, is that consistancy is all important. The specs for float height tolerance is usually 1mm. Also don't be afraid to try different heights within a couple of mm's as a tuning method.


    Also remember that carbs should be the last item on the agenda when tuning or resolving running problems. Compression, cam timing, valve adjusting and ignition all should come first. Those will all effect carburation and carburation will not effect them.
     
  12. Llenroc

    Llenroc F1 Veteran
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    #12 Llenroc, Apr 22, 2005
    I am not sure if this has been mentioned before but I have always used two sync gauges seemed to make it easier to balance carbs I didn't have to move the single gauge back and forth between throats and banks.
     

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