idle and emulsion for twin 40

[russlea]

hi guys,

ive got a 1.4 running twin 40's (dcoe). the only problem is that the guy who i brought them from had them set up for a 2 litre. i need to drive it quite far to the rr, and because its overfuelling massively its not running well. ive just got new main- size 115, and air- size 165, with size 40 pump jets but what idle jets do i need roughly?? also do i need to change the emulsion tubes coz there frickin expensive!!!!

cheers

[dan23]

you will have to change the emulsion tubes

are your carbs weber or dellorto
speak to euro carb they have a shop on ebay if you tell them your engine they supply the bits you need

when they have told you the corret spec you need post it here before you buy from they that way other members can advice you as i got my bits from them an i cant my carbs to run (but they didnt run before either)

[dan23]

http://www.dellorto.co.uk/

use this mate i cant find their ebay shop

[MC]

Whatever jets you buy, there is a chance that they will be replaced by the rr operator. They normally just swap them and don't charge.

Here is a basic rule of thumb for a 1.4 on Weber carbs and this will depend on the level of tune:

Basic engine: 28mm chokes, 110-115 mains, 160-165 air, F15 emulsion, 35 idle.

Modified engine: 30mm chokes, 120 mains, 170 air, F9 emulsion, 40/45 idle.

The idle jet does not control idle fuelling, just the transition between idle and and main fuelling. If the car hesitates on opening the throttle, go up a size. If the car hunts then go down a size.

Turn the mixture screw fully in, then trun them out 2.5 turns. Get the engine started and use a balancing tool to get the balance spot on. Use threadlock to stop this moving. Adjust the idle to around 900-1100rpm and then set to on the idle mixture.

With the engine warm, one cylinder at a time, open the mixture a 1/4 turn and observe the engine speed. If it increases continue a 1/4 turn at a time. If it decrease, turn back in 1/4 turn.

During this process use the idle adjustment to keep the revs around 1000rpm. Keep working on each cylinder until adjusting any of the mixture screws in any direction results in the revs dropping.

This should be sufficient to get you to the RR.

MC

[russlea]

brilliant thanks guys