X1/9 1300 DCNF Jetting

[GPW]

Hi Guy,

After many hours welding I am now about to rebuild my X1/9 to modified sprint/hillclimb spec to compete in the under 1400cc catagory

So I am ready for spring I am refitting the original 1300 engine in my Fiat X1/9 and want to fit my twin Weber 40 DCNF carbs. The engine is for now completely standard apart from the carbs, CSC 4 branch manifold and system. I would be very grateful if you could give me some advice on appropriate jetting for the carbs. The setup at the moment is :-

Choke - 30
Main jets - 140
Idle jets - 65
Emulsion tubes - F36
Air corrector jets - 210
Accel pump jets - 35
Aux venturi - 2.5
Needle valve - 1.75

To be honest I have no idea what these where jetted for so don't want to try running the 1300 without first getting a reasonable baseline to work with.

I have aready read and taken your advice for a Silver Top fast road pump with no regulator.

Any advice would be gratefully accepted!
thanks as always
Guy

On another note I have found a company that is suppling X1/9 manifolds as well as many others thought it might be of interest

LINKS BY PERMISSION ONLY READ PROTOCOLS
GC

[GPW]

Sorry about the link Guy

missed that in the rules. Won't happen again. Just thought it would be useful to all members finding it hard to get a manifold for there project. I haven't used the company myself as my carbs came on a old manifold like the one in the photo.

Apologies again

Guy

[Guy Croft]

It's OK. Remember I'm only a PM away though!

GC

More later..

[Guy Croft]

Original standard X19 1300 on 40DCNF

Choke - 30 - OK but a bit small - 32 better
Main jets - 140 - too big (rich) go 120
Idle jets - 65 - too rich - go 45
Emulsion tubes - F36 - no - use F21
Air corrector jets - 210 - maybe a bit big (lean) go 200
Accel pump jets - 35 OK

The performance will depend to a very great extent on the layout of the ex manifold and back pressure in the silencer.


GC

[GPW]

Many thanks Guy,

I have started ordering the parts. The F21 emulsion tubes are being difficult to source. I have tried Webcon who no longer supply the F21 and supersede onto the F22. The difference according the Webcon is the F21 tube has a diameter of 5.7mm and the F22 is a 6mm diameter. The hole layout of the two tubes is the same. I have also tried the usual Google search but nothing there either.

What do you advice? Or do you have any F21's that I could purchase from you?

Regards

Guy

[Guy Croft]

You can certainly use F22, no worries, they are interchangeable with F21.

GC