I have this setup on my UK 1500, in the UK we don't have such strict
emmissions, my car currently has 4* in the tank!
Dirty air filters, oh and wrond type of air filter and housing if you don't
have the correct filters and housing you chainge the mixture!
Are you shure that your not too lean, this leads to high CO emmissions and a
OK these are general rambelings that I hope you will be able to use to find
If you have unleaded it will be more sooty, the lead in the petrol helps for
a cleaner combuston.
One thing I would ask is what is it faileing on. HC emmissions, or CO
Here are some thing for you to chew over!
Are your needels sticking down.
Gunssions colour tune might help when setting up the carbs!
It mabe that your carb piston springs are too heavy, pushing the pistons
down too far. This happens and the air speed over the jet increeses causing
more fule to be taken.
I would recommend the Hayns SU carburetter manual, I think there Webber and
Solex one has it in as well. Read up on the theory of constant depression
carburation, I'm very sad and find it very interesting!
What's your vachume like?
Is your dizzy set a 10deg BTDC and does it have a "home market" advance
Anyway some data for twin carbed 1500's
Carb Spec Needle Piston Spring Jet (F/R
1974/76 AUD665 CUD1041 AUC4387 AUD945(1/0)
1976/77 FZX1258 CUD1041 AUC4387 LZX132(3/2)
1977/79 FZX1122 NZX4013 AUD4355 LZX133(1/0)
1979/80 FZX1327 NZX4013 AUD4355 LZX133(1/0)
Sizes Top to Bottom in regular intervals
CUD1041 = ABT = 0.089", 0.0785", 0.0722", 0.0678", 0.0645"
NZX4013 = ADN = 0.090", 0.0802", 0.0732", 0.0700", 0.0678"
AUD9450 White Band Red Jet Head 0.09" Jet
AUD9451 Black Band Red Jet Head 0.09" Jet
LZX1322 No Data
LZX1323 No Data
LZX1330 No Data
LZX1331 No Data
Unfortionatly I can not decode thoes needel values, my guess is they might
be just slighty bigger than 0.09" but with the relivent needels the later
combination would present the leanest idle mixture.
I would try ordering the latter new parts as a last ditched attempt.