Drilling FRD B 34's vacuum port

[farmer rob]

Hi Guys, I am building a trials rail engine for a friend, he wanted to use a pair of Dellorto FRD B 34's on the build but it seems the pair he has, has not got the dizzy vacuum ports drilled. As he needs it for low-down throttle response he wants a SVDA dizzy and not a 009. I wondered if someone could tell me the measurements of where the port should come out in the throat of the carb and what diameter the hole should be

Many thanks Rob

[V8Nate]

I haven't heard of drilling the baby dellorto's only kaddies but here's a picture of where the vacuum ports are on a set of dell's i just got rid of.

[farmer rob]

Hi V8nate, thanks for the reply. Both carbs have got the external brass fittings on them but the carb boddies have not had the final drilling done in to the carb throats. I can remove the plugs to check the other drillings but need to know at what height the drillings need to come out at compared to the throttle butterfly or carb base and the diameter of the drilling

Cheers Rob

[V8Nate]

Damn wish I could be of more help, I take it you are wanting the vacuum to come into play slightly after throttle opening.

[farmer rob]

Yes that is right!. if no one can help, I guess I will have to measure my 34 ICT's and solex carb's and work out an average of where it should be lol

Cheers Rob