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Registered:
February 2005
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2T-B Carb adjustment help needed
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Thu, 11 August 2005 20:31
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Hi
I finally got airfilters and everything i need on my twin carbs now, the carbs react and run very good, but i still have a problem with getting them to idle correctly.
now they idle at 1000rpm, but under that the engine just dies, but at 1000rpm it idles kinda rough, you can hear very good that two of the cylinders only fire like every 2 seconds.
does anyone have a good prosedure for how to adjust theese carbs pretty good, is there any smart things i can do to figure out why the 2 cylinders is misfirering, or how to adjust the carbs so i can make it run normal again.
1000rpm is still high for idle tho?
thanks for any help 
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Location:
Canberra
Registered:
May 2002
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Re: 2T-B Carb adjustment help needed
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Fri, 12 August 2005 05:32
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Engine turned off.
I assume we are speaking of twin dowdraught type ASIAN carbies.
If so, gently screw in the idle mixture screw, located at the base of the carb, until it just stops. any further, and you will put a lip on the needle.
Next step is to unscrew the the needle by 2.25 to 2.5 turns.
This will set the mixture, as close to factory as swearing.
Do this on both carbs.
Then start engine.
Next you need to adjust the idle on each carby, If you have got this far, I think you will know where to adjust idle screw, its on the side of the carby. Adjust each carb in turn, ie, screw in the idle screw until you hear a positive rev rise, then knock it back a little, do the same for both carbs.
Anywhere between 650rpm and 850rpm is a good idle for a jap 4 cyl engine.
This is the part that I cant remember(benn too many sleeps and beers), but there must be a balance adjuster, on the linkage between each carb, set this to give a smooth balanced idle.
Check and adjust ignition timing if required.
If you still cant get em to run by this point, I am afraid it is probably time for a coupla carby rebuilds.
Hope this helps, cheers Chuck.
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Registered:
May 2005
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Re: 2T-B Carb adjustment help needed
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Fri, 12 August 2005 06:40
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with the balance, screwing it in too far will open the left carby too far, screwing it out too far will open the right one too far.
make sure the idle stop is touching on both side, adjust the balance to make sure. If u ahve a vacumme gauge u should be able to use this.
with the mixture, if they arent factory items chances are the jets have been change and so on. so screw the miture out about 2 turns then turn it about quarter turn and wait 5 seconds or so. try and find the highest atainable idle,
so start with number 1, find its highest idle with the mixture, once done lower the idle and go to number 2, get the highest idle then knock the idle down. so on for the rest.
hope i made sense
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Location:
Canberra
Registered:
May 2002
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Re: 2T-B Carb adjustment help needed
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Sat, 13 August 2005 08:09
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Yep, thats the way to adjust sidedraft Solex's/ Webbers.
cheers Chuck.
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Registered:
February 2005
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Re: 2T-B Carb adjustment help needed
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Sat, 13 August 2005 13:36
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Thanks for ur answers
Yes its asian downdraught carbs
I have tried to adjust them like you guys said now, but still not any better, it idles around 1000rpms and sometimes it jumps up to 1500, and goes back down to 1000 again.
i have opened the carbs, cleaned them and such, and the carbs seems to be very good. Im starting to think its something else with the engine.
my old carbs was a real mess, but it also idle like this, ruff and wouldnt idle under 1000 no matter what.
i also noticed its a bit oil in the sparkplug holes sometimes, i dont know if this is normal for theese 2t's, or is it a sign that my engine is fukked?
From the top cover there is two hoses, one is supposed to go to the manifoild, and the other to the airfilter, i guess it doesnt matter wich of them goes where?
anyone know whats going on with my engine?
thanks again
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Registered:
February 2005
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Re: 2T-B Carb adjustment help needed
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Sat, 13 August 2005 16:18
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Also the airfilter box has a hole located on the buttom left end of the box when u stand infront of the car looking into the bay. is there supposed to be a hose in there? if so, from where? my 2t seem to have only two big hoses and they are already in use.
seems to me like the car sucks very little air when i hold my hands on the airfilter box hole, normally the car should stop if i do this?
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