Weber dcnf 40 problem to helm me

Jimgkioulis

Jimgkioulis

Daily Driver
Hi all friends. O hVe a problem with my fiat 128. I have 1500. Biger port head. Ansa 421. Little compresion up. Electronic ignition. Catcams 278. I job with dcnf 36 perfect. I put now dcnf 40 and at ow rpm 1600 -2300 do brakes. I balance perfect. I do difener setting but nothing change it and job like 36 dcnf. My setting now is 135 f22 200air 30 venturi 55 indle 4.5.
 
I think he's saying he has a 1500 with big-valve head, Ansa 4-2-1 exhaust, slightly raised compression, Cat Cams 278 cam grind, and electronic ignition. He had it working perfectly with a 36 DCNF, then changed to a 40 DCNF. Now it's not working between 1600-2300 rpm (breaks up?). He says he balanced it perfect, so I'm guessing it's dual carbs.
Jetting is now 135 mains, F22 emulsion tubes, 200 air correctors, 30mm venturis (chokes), 55 idle jets, and 4.5 aux air venturis.

Those specs look like what others have run, though my notes show people using 32mm venturis.
 
Kind of what I thought he meant, but wanted to clarify. 1600-2300 rpm seems like rpm that is heavily supported by the idle circuit so I guess the first thing I would do is try larger idle jets. What was the jetting of the 36 DCNFs?
 
hi! the problem now is ok!!!! i do anything! i put biger venturi 32 and now the car is perfect!!!! for all rpm! the car is 107hp. i dont have biger valves. i have normal original valves. only biger port head and compresion. catcams 278, doubles dcnf 40, ansa 4 2 1, electronic ignition.is good 107hp and 14kg? thanks all peoples to respond me fast for help!
 
128kid said:
I think he's saying he has a 1500 with big-valve head, Ansa 4-2-1 exhaust, slightly raised compression, Cat Cams 278 cam grind, and electronic ignition. He had it working perfectly with a 36 DCNF, then changed to a 40 DCNF. Now it's not working between 1600-2300 rpm (breaks up?). He says he balanced it perfect, so I'm guessing it's dual carbs.
Jetting is now 135 mains, F22 emulsion tubes, 200 air correctors, 30mm venturis (chokes), 55 idle jets, and 4.5 aux air venturis.

Those specs look like what others have run, though my notes show people using 32mm venturis.
Click to expand...

Courtney, you nailed it!!!
 
all is perfect! but is good 107 hp with this i have? have any x1 or 128 with dynometer with the same parts? thanks.
 
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