What is the standart jets for a 1442 engine?

[Moes]

Hi

I am having some problems finding out the "standart" size of the jets, in a pair af weber dcnf36 on a 1442ccm engine.  
 
In my manual it says that the jets size is:
Main-jet:                 120,  
Air-adjustment-jet: 185,
Starter-jet:             70F5 or 70F10  

that is on a 1294 engine.

I believed that when it was the same carburettors on my 1442 as on the 1294 engine, then the air/fuel mixture and the jets perhaps should be the same. But...

on both the two pairs of carburettors I have, some of the jets have been different from the manual:
Main-jet:                 130            125
Air.adjustment-jet: 210            205
starter-jet:             120F5        70F10

The main-jets and the Air-adjustment-jets are not that different from the manual, but there's a big differents on the starter-jets from a 120F5 to a 70F10  

I am curious to know what jets you "bagheera drivers" are having in your carburettors, or what the standart size is?    

kind regards Frederik  


    

[Spyros]

Fred,

Saturday, I'll try to take the time to check what I adjusted on different of my engines.
But. Starter jet ?
I always tried to avoid playing with starter.
Also you need to think that the purpose of the carburator is to produce a stoechiometric mixture.
If you increase the fuel supply then you need to increase the air supply. These goes together.
In between, you'll have the emulsion tube (F36)
He will determine the carburator response.
A F36 is a kind of general purpose tube.

[Spyros]

210 -130 on 1440
185 - 120 on 1290
Are common values for the main jets.

Before speaking of the starter jets, what are the numbers on the back of your carbs ?

[Moes]

thanks  

On the back of the carburettors on my bagheera it says: 36DCNFA 50 100 6H on the first one, and 36DCNFA 49 100 6H.

On the pair I have as spare it only  says:  3  on both af them..

I hope that is useful  

[roy4matra]

thanks  

On the back of the carburettors on my bagheera it says: 36DCNFA 50 100 6H on the first one, and 36DCNFA 49 100 6H.

So your pair of carburettors are the '49-50' which were fitted to the 3G4 engine.  The 6Y4 engine had the '51-51' spec.

There are quite a few differences between versions so you should always check those figures to know what the specifications actually should be.

The 3G4 is the 1294cc engine so if you have a 1442 you really should set the carbs. to the '51-52' spec.

These are the specs:
'49-50'                              '51-52'
Venturi: 29                        30
Main jet: 125                     130
Air correction jets: 200        210
Idle jets: 45                       47
Pump jet bleed: 45              40

All other settings are the same.  They should both have the F10 with 70 up to 1977 when they changed to F4 and 80

I think you can still ask your Weber agents for copies of spec sheets if you need them.  My agent has always been helpful when required.

It sounds like someone has been playing around with your carbs. and swapping bits without knowing what they were doing!

Roy

[Spyros]

Well well,
From experience, I need to say that a pair of 49-50 or 51-52 will bring less difference that badly tuned carbs versus correctly tuned ones.

If you are really interrested, the DCNFA refers to post 1977 carbs with different starter
Rather than 70F10, it should have been something like 80F4.

[Moes]

Hi Roy and Spyros

Thanks for your replys, it's a great help.

I'am going to Le Mans this year
I hope and belive that my Bagheera can be ready some time before Le Mans. I haven´t realy decided if I'am going to drive the 1200km to Le Mans in my Bagheera if it's ready, but I would love to do it, if I dare    

I'am wondering about how many from the Matrasport forum that is going to be at Le Mans 2010? but there is probably going to be a thread about that later.

Frederik        

[Anders Dinsen]

Great to hear about your plan, Frederik!
I'm going to Le Mans this year. Not in the Murena, though - we'll take the Grand Espace like we did in 2008.
Good idea about starting a thread. It's not too early!

/Anders