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Drilling FRD B 34's vacuum port

Posted: Sun Nov 22, 2020 9:53 am
by 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

Re: Drilling FRD B 34's vacuum port

Posted: Sun Nov 22, 2020 10:27 am
by 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.Image

Re: Drilling FRD B 34's vacuum port

Posted: Sun Nov 22, 2020 11:05 am
by 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

Re: Drilling FRD B 34's vacuum port

Posted: Sun Nov 22, 2020 11:29 am
by 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.

Re: Drilling FRD B 34's vacuum port

Posted: Sun Nov 22, 2020 12:30 pm
by 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