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Registered:
June 2004
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5K Carb Tuning ?
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Mon, 19 July 2004 06:12
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Well..iv finally finished putting the 5K carb onto my 4K manifold, and after about 15minutes of trying to get the thing started, it did, just not quite how i would have liked it to, it sounded like it was revving very high which im sure must have something to do with the tuning of it ?
Now, theres two screw like things with springs on the side of carb, one down near the where you mount it, and the other over by the accelerator butterfly, how do i tune the carb, is in, which way do i turn the screw like things so it is normal again, it never revved like it does with the old 4K Carb..
- David
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On Probation
Location:
North East NSW
Registered:
December 2002
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Re: 5K Carb Tuning ?
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Mon, 19 July 2004 13:12
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the horizontal screw at the base of the carb, facing the strut tower is the idle mix screw. it's a fuel bleed, so out is richer. there are two screws that stop the throttle from fully closing, one is connected to the choke and changes how much throttle opens when you have the choke on, one comes out of the carb body and is the stop for the throttle wheel itself. you should be able to see which is which by actuating the choke, tune it for best lean idle, and best vacuum, at 800~1000rpm
obviously make sure your timing and tappets are set properly first, and the engine is at operating temperature
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Location:
tallahassee FL usOFa
Registered:
May 2002
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Re: 5K Carb Tuning ?
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Tue, 20 July 2004 14:55
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those are just its most basic adjustments.
tuning involves checking/setting the float level and jetting changes for the idle, main, air correction, accelerator pump and whatever.
DO NOT screw in the idle mixture screw too tight. it will damage its seat. it should be about .5 to 1.5 turns out for a smooth idle.
if you are able to screw it all the way in and it still idles & doesn't die/stall, then the carb needs some work.
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On Probation
Location:
North East NSW
Registered:
December 2002
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Re: 5K Carb Tuning ?
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Wed, 21 July 2004 00:10
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you'll find the aisans are a bit more restrictive than that. you can change the float level (factory 5k will do), main jets, and you can try tuning the accelerator pump by putting a slightly weaker/stronger spring on it but it's hard to get the right parts. mine fuels up and stalls if i actuate the pump too much at idle
you reckon 1.5 turns? i've had k motors that won't idle at anything less than 5 turns, but then again i don't run a choke do i 
out of interest zgen, why did you ugprade to the 5k carb? did it have any bigger throats or venturis? what measurements? i thought 4k-c and 5k-c carbs were the same thing? is it going any different up top?
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Registered:
June 2004
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Re: 5K Carb Tuning ?
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Wed, 21 July 2004 00:45
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Hey
thanks heaps guys, iv had a play with it, and still havent got anything changed  so il prob have to take it to someone to fix,
as for changing to the 5K Carb, my 4K had a rooted jet and accelerator butterfly and a 5K carb one was offered to me first and was cheapest out of another 4K one for sale..
- David
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