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side drafts or down drafts??


Guest olschltoy

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Very wipe topic to cover, but really, a carb should be chosen to suit the engine, not the other way round. T

here are so many differnt carb's avalible its not funny. There is no real answer to this question. You can have a single down draught like a 32/36 or 34 adm or the v8 sorta range of carbs, holly's n demons ect.

I have twin down draughts, exactly the same as a side draught but made for verticle aplication. The only disadvatane of this type of carb over a sidey is it doesnt flow as well because of the 90'' bend. But i doubt you'd notice the difference if you bolted up the same size side draughts to my engine.

Cant really attempt to answer the question with out any details of your engine.

Def'

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Hey I have a question. I got the 32/36 bolted on and running on the 4G63, but it's clearly running lean. Aside from re-jetting, (not worth prohibitive cost) is there anything I can do to increase fuel flow? I have no idea which screws do what on a weber, so maybe that's a good start!

I eventually plan on running twin sidedraught 45s or something to that effect, but need it to be going now. My standard carb=in bits and many of aforementioned bits missing. Man that made me sound like the chronic n00b, spose I am really when it comes to carbs.

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You want to adjust the air/fuel mixture screw. I've tried playing around with it but its kind of hard to tell what your doing unless your good with carbs. Your supposed to turn the idle up a bit, then fiddle with the screw till you get it right and then wind the idle down so that it runs smooth. It's fairly obvious which screw it is I think.

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You want to adjust the air/fuel mixture screw. I've tried playing around with it but its kind of hard to tell what your doing unless your good with carbs. Your supposed to turn the idle up a bit, then fiddle with the screw till you get it right and then wind the idle down so that it runs smooth. It's fairly obvious which screw it is I think.

What did the carb come off? why don't you take the jets out and give them a drill i fyou have access to precision drill bits?

The screw that goes into the baseplate of the carb in on an angle from the throttle linkage end is the mixture screw... its quite bad to run your engine lean though.. try screwing it in untill it is about to stall then on 1.33 - 1.5 turns outwards...

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Hahahaha yeah know how you feel RT

Anyway went and did that, screw was WAY out, took about 5-6 turns to get it to the point where it was about to stall. Then did just under 1.5 turns out, and turned idle down a touch, seems to go ok, won't know till the builders get the fuck out of my driveway so I can take it for a test.

One thing I've noticed since putting this carb on, is the way a lot more water and dirt comes out of the exhaust when cold. Not HEAPS, but enough to notice that it's clearly more than the solex. Not really an issue since water=product of combustion, but interesting all the same

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man, everytime I tried to tune a carb it got progressively worse each time I touched it. :rolleyes:

Haha yeah that happens... or when your jetting carbs you can't remember if its better or worse and shit... and its a cunt to change it back the anoying thing is you have to go to far then go back but its hard to tell whats happening

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Hahahaha yeah know how you feel RT

Anyway went and did that, screw was WAY out, took about 5-6 turns to get it to the point where it was about to stall. Then did just under 1.5 turns out, and turned idle down a touch, seems to go ok, won't know till the builders get the fuck out of my driveway so I can take it for a test.

One thing I've noticed since putting this carb on, is the way a lot more water and dirt comes out of the exhaust when cold. Not HEAPS, but enough to notice that it's clearly more than the solex. Not really an issue since water=product of combustion, but interesting all the same

Water a product of combustion? i really don't think so.... but i could be wrong.. :D

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A petrol engine is a classic example of the utilisation of a machine to

produce work from the combustion of a fuel which is, in this case, petrol.

If we represent petrol as being composed of n-octane, we can write a global

reaction of n-octane oxidation:

C8H18 + 12.5O2 -> 8CO2 + 9H2O

The reaction above indicates the complete combustion of octane to give

CO2 and H2O. In the engine however, the reaction is simply not represented

by the above equation and in fact the products from the exhaust contains

more than just CO2 and H2O, which depends on the amount of air that has

been added with the fuel. The chemical processes involved in the engine are

complex. It entails a complex free-radical chain reaction mechanism,

involving many chain carriers and branching agents with the ability to

react in a number of different ways.

http://www.madsci.org/posts/archives/ma ... .Ch.r.html

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