use of a smaller carb - effect!!

[KKV270]

Hi.
Say I used a well tuned 30 pict on a 1600cc engine what would the most of an effect (negative) be?? (this is assuming I got it sitting on the 34 pict manifold and did the tuning of the engine using the very same carb!!!

[darzoom]

The 30 was used on the 71 1600. It has lower airflow due to a smaller venture (throat) and we all know more air is more power in the equation Suck/Bang/Blow. Below is the list of carbs used when.

Carbs used when:
30PICT/1 - 66 and 67 1300/1500cc
30PICT/2 - 68 and 69 - 1300/1500cc
30PICT/3 - US only 1970 1600cc single-port engine
All have the same sized 24 mm venture and all have the same airflow. The difference is the difference circuits inside and other improvements for better fuel/air mixture control but no improvement on overall airflow.
31PICT/3 - 71 1600cc Dual Port - 25.5 mm venture to increase airflow
34PICT - 72 and later 1600cc dual port - 26mm venture - will not fit on manifold without adaptor.

[KKV270]

Thanks Darzoom

So I guess the effect amounts to "less bang".
Well, my engine is a rebuild of salvaged workable parts from here-there....with 1600 dual ports (each head yet again being different- one from Brazil, the other probably not sure...didnt see the label).
It runs well...

What about altered jets (probably fitting larger ones....any recommendations?...that is, if using the 30pict 3 on the dual port!!!
Cheers.

[darzoom]

Actually, it is smaller suck (smaller venture) hence less bang.

Try a 55 idle jet, 125 main jet and 125 or 130 air correction jet. Leave the 65 power jet (right side) as-is. It is a good starting point.

There are tons of threads on jetting the 30PICT online. Good hunting.

[KKV270]

Cheers

[Blue Baron]

The 30 will fit and run fine, but you will need a manifold adapter.

[KKV270]

Thanks.
I managed to tweek my 34pict that works very well.
I earlier fit the 30 with firm gaskets and a tight bolt/nut (without an adaptor) and run around but only allowed that for a short while.

Thanks.