ChrisT
Club Retro Rides Member
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Club RR Member Number: 225
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Balancing twin webersChrisT
@christ
Club Retro Rides Member 225
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Anyone got a simple guide on how to balance and set-up a pair of weber DCOEs? Used to have a really good one I found online somewhere but can't find it now  |
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You need to get yourself a synchroniser really to do it properly.
The balance is adjusted via the screw in the centre of the linkage that links the 2 carbs together. With a synchroniser and the engine running you can see what each carb is drawing in.
If they are out then turn the screw so that you can bring the carb drawing the most down to the level of the one that is drawing the least. If needed then bring the idle up using the idle adjustment screw. When they are the same they are balanced.
When its right there shouldnt be any rocking of the engine. And it should idle fairly stable assuming your idle mixtures are right.
If needed, ill happily type up a more in depth write up with pictures on how to set up both the balance and the idle mixtures but i cant do that here as I'm at work so will have to wait till i get home.
Alternatively you could bring the car down here for a proper set up on my rolling road :-p
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ChrisT
Club Retro Rides Member
Posts: 1,638
Club RR Member Number: 225
Member is Online
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Balancing twin webersChrisT
@christ
Club Retro Rides Member 225
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Cheers for that - it's pretty much what I thought but I seem to be getting nowhere doing it today. Haven't got a fancy synchroniser, just one of these....  It's worked fine before The engine's rocking quite a lot so I assumed they were out of balance and adjusted the linkage between them but I'm getting such an uneven idle and spitting back that using the balancer is difficult - putting it over any of the inlets causes the engine revs to rise so I can't get an accurate reading oh well - try again tomorrow |
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If its spitting back thats indicating that its lean on that barrel.
The rising idle is the drawback of that type of tool. The one i use doesnt interupt airflow.
Screw down your mixture screws all the way in and then undo them 2 1/2 turns and see how if it still spits. Your then looking for slight increases in idle. Turn the screw out 1/4 turn at a time on one cylinder waiting a few seconds in between to allow it to settle, If the idle rises slightly then your going the right way. If it falls then turn the screw in and again look for increases in idle. If you have to deviate to far from the original 2 1/2 turns then your idle jets are wrong. Turning out richens so if too far out then too small a jet, to far in means too large a jet.
Hope that helps.
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get a bit of petrol pipe... stick it near your ear and hold it near but NOT IN the intake of the carb, then listen to the other one... you will hear the difference... this is how my gaffer used to balance them and he was well known locally for getting them running sweet as...
(think a well set carb sounds like someone scratching cardboard if that makes sense... seems to work on the monkeybike lol)
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bstardchild
Club Retro Rides Member
Posts: 14,901
Club RR Member Number: 71
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Balancing twin webersbstardchild
@bstardchild
Club Retro Rides Member 71
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get a bit of petrol pipe... stick it near your ear and hold it near but NOT IN the intake of the carb, then listen to the other one... you will hear the difference... this is how my gaffer used to balance them and he was well known locally for getting them running sweet as... (think a well set carb sounds like someone scratching cardboard if that makes sense But before you do that check the butterflies on each carb are opening the same Ideally a couple of same size brand new 1mm - 2mm drill bits is perfect Put one under one butterfly and if you can't fit the other under the other or it's loose then you need to sort that first When that's sorted then a piece of 1 - 1.5 inch hose 2 ft long is all you will need to balance them up doing tripple carbs gets your head scratching  but twin is fairly straight forward |
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ChrisT
Club Retro Rides Member
Posts: 1,638
Club RR Member Number: 225
Member is Online
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Balancing twin webersChrisT
@christ
Club Retro Rides Member 225
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ah yes, liking that idea - was trying to think of a way of making sure they were open the same amount, cheers
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Was this 'sort of' the guide you were looking for? I know this is on the 'Capri Laser' Page but I seem to remember it was identical to the one on a 'Kit Car/Lotus Seven' page. www.fordcaprilaser.co.uk/weber_dcoe_carbs.htmPlease remember this one will be biased towards Ford engines so not to sure if things like emulsion tubes, idle jets etc. will be incorrect etc. |
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