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Worked 5K, Twin Dcoe 40 Tuning

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Hey lads, been a while since ive posted on here, been buying motorbikes and riding them instead of playing with the poor old corolla in the corner.

 

Anyways wanna beat the rego running out on july and have the car back up and running and on the road all sweet.

 

at the present the bottom end is sitting on a stand wrapped in glad wrap waiting for me to install the pistons, rings, and rods then slap on the head, all balanced, blueprinted and ready to go, was just waiting for my cam.

 

 

Engine is setup with 40thou over 5k. 11.6:1 CR, 5k worked head 1mm Oversized Intake/Exhaust Valves, Port work, Approx 6kg flywheel, 284 Duration 495 lift cam. Twin 40mm DCOE webers, i have just obtained 32mm chokes but also have 27mm that came with the carbs.

 

The webers specs i have are - 40 DCOE32 no. 109114 & no.107111. 27mm chokes, 4.5 F9 45 idle jets f9 air drill 170 air corrector f9 emulsion tubes and 112 main jets

 

 

IS there any one out there that can help drop some suggestions into a setup that will suit the run-in of the motor - not wanting to be too lean, and not wanting to tow it to a tuner when it needs to be run in to start with.

 

I know that i could slap on the carbs as they are, but i bet i can get closer to start with. Ive found some info online and some lost programs that suggested what jets but I'm at a dead end.

 

 

As for the assembly of the engine, I'm hoping to assemble bar genuine toyota head gasket, 1 piece manifold gasket, and the correct length pushrods this weekend.

 

As for tuning this will be once my engine bay is painted and i finally pull my finger out to drop her back in, All achieveable in a short timeframe,.

 

 

Any info into my final stages would be good,. I'm all ears and keen on finishing this old girl off and spending some time on the road with it

 

 

 

Cheers

Before you go to far just make sure that there are performance carbs not emission carbs .

 

To tell take out idle jet it should have 2 treads on it performance ,if its emission type will have a washer near to the top of jet and 1 thread .

 

Also check to make sure they have the same number of progresion holes or you will never tune them.

 

Not even weber can work out they numbering stamped on to they carbs ,so many different types.

 

Just had a quick check of the jetting chart i have based on about 380 cc per cylinder.

45f2

130-135 mains

32venturi

4.0 aux venturi

f16 e tube

40 pump jet

1.75 needle valve

don't take this as correct as each engine will vary ,and this sounds like a very hot engine

 

rob

  • Author

Hey thanks for the response Rob. Ive checked over the idle jets and they are the performance style like you have explained. Ill try and chase up some larger mains and different e tubes. Keen on hearing what else anyone out there is running in theirs.

 

Cheers

  • Author

After doing a bit of searching i came across recarbs setup to suit 3-4-5k. Settings look a bit different and pretty broad. Surely theres some theory behind choosing correct jets??

Carburettor jetting:

* chokes 32

* Main jet 138

* Air jet 190

* emulsion F64 - F47

* Idle jet 59F21

* pump jet 35

I figure the theory is that you have to hit a dyno or fit an oxy sensor & fuel mixture display to get it right.

 

They will tell you the fuel:air mix under driving conditions, but it all depends on porting and cams and cam timing and compression and ignition timing and...

 

So most stuff is pretty broad in scope. I've seen graphs of Weber jet usage, but the 'lines' are areas on a curve.

Keith is right in the end it needs to be dynoed to get the best out of them.The recarb ones i think dcom which are different again.

 

When its all said and done you will have jetting nothing like whats suggested as it will be jetted to that engines needs only.

 

Remember that all jetting charts are a guide only.

 

I deal with weber in Melbourne ,his good bloke and no,s what his talking about.

 

New players also be careful of the new cheap so called weber look alikes quite nasty ive been told.

 

Rob

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