H30/31 pict solex ....set up?

[mikemango]

Sorry for all the questions tonight guys.
I've got a late AS model 1600 twin port engine with a solex H30/31 pict carb, currently running 009 dizzy, i'd like to get away from the 009 by replacing it with a svda type dizzy but have been led to believe that this combo is not a good match.
Would i be better to:

1 fit a vacuum only dizzy
2 Keep the 009 and put up with the flat spots (ghrrrrrrrr)
3 get a solex 34/3 carb and run that with a svda type

is there a noticeable difference between the two carbs?
:roll:
mike

 

[69calwesty]

hi mike - i'm having some carb problems but one thing I have found out is that the 34 pict carb doesnt fit the 30/31 manifold. The 34's a bit bigger – the only way to fit, by the look of it, would be to change the manifold. To do that the engine has to come out, is it really worth it?

The advice I've got is stay stock or go twin – but with twin you've got to be prepared for the setup and getting someone who knows what they're doing and that you can take it back to.

Good luck with it.

 

[bigdaz]

i didnt notice much difference between the two carbs. the 34 is bigger so should produce more power but in practice it wasnt that noticeable on mine.
as 69 westy said if you have a small flange manifold you will have to swap it for a 34 one. This can be done without dropping the engine but its a fiddle.
if you have a 1.6 tp i would have thought that it would have had a 34 originally. so the 31 might be on an adaptor plate already so the 34 will go on ok.
the 009 should work ok but you need to time them with the engine revving at about 3500 revs and set the top end rather than the bottom.
this is because 009 seem to vary in the way they advance and if you set it up static as usual 7.5 degrees. you might only be getting 20 or so deg advance or too much say 40 degrees. you need to be around 30-32 i think. too much will blow the engine and too little will make it sluggish.