Putting a 2nd hand 1835 together and it came with a 40 DCN with 24mm venturis, 130 mains and 200 air correction jets, considering this is made for a 1200 Fiat I need to make some changes.

Dad had some 32mm venturis off a buggy he owned 20 years ago, so I'm fitting them. I would like to know what main jets and air correction jets would be a good start. The engine may have a sports cam and may not.

I'm getting the carb acid washed and stuff by a carby bloke in Ipswich.

is it a single carb or duals??

Computer says it does not know of any 1200 Fiats that had 40 dcn weber fitted but closest match to your request from data base is for a stock 1600 twin port engine with 1 x 40 DCNF 12

32mm venturi
1.60 main jet
0.55 idle jet
2.20 air correction
F24 emulsion tube
0.50 accelerator jet
1.75 Needle valve

Hey Rob

ive used plenty of those carbs
my old 1835 that u got the parts from had twin 40DCNs and theyre a good old carb cept the fuel bowls are tiny and lack of cold start enrichment sucks in winter
24 vents are way to small for an 1835
so if u can get the 32s use them
130 mains is what i use for 1600s so
140-145 would prob be on the money for an 1835 in a single setup
and for idles id say around 60-65 and airs anywhere between 180-200
DCN dont actually have E tubes only the later DCNFs did

-Joel

Joel Im sorry but they do have Emulsion tubes they're just not connected to they mains like the other webers. The ones in this one were F38, not easy to get out either.

Bizarre its a single.

DCNF is pretty much they same but you can take the main jets out without having to open it up again.

The carby bloke told me that the numbers on the carb indicated it was off the fiat.

Carby is all cleaned up and awaiting reassembly.