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Best jets for 1971 Beetle 1300 Twin port

Posted: Thu May 17, 2018 11:16 am
by 73type2
What is the best sizes of main and air corrector jets to be used on a 1971 Beetle 1300 twin port at the coast?

Re: Best jets for 1971 Beetle 1300 Twin port

Posted: Thu May 17, 2018 12:20 pm
by Dawie
When dual port 1300 was introduced late 1970 (for the 1971 production year), it had unusually big jets, but this was found to be a problem, so VW changed to smaller jetting during the first year.
With it's original German 31PICT carb with 25.5mm venturi, they used 130 mains and 110 air correction.

Re: Best jets for 1971 Beetle 1300 Twin port

Posted: Thu May 17, 2018 3:14 pm
by 73type2
Thanks Dawie. I'm currently running with a 145 mains and 170 air correction in my Brosol H30/31 carb. I also have a set of 120 mains and 110 air correction. Should I stick these smaller jets in there? I don't have a 130 main jet.

Re: Best jets for 1971 Beetle 1300 Twin port

Posted: Fri May 18, 2018 11:41 am
by Dawie
That 120 main jet is too small for use in combination with the 25.5mm venturi in that carb.

Vw themselves did use smaller jetting in certain applications. Like the USA- version 1600 twinport beetle, which had 127.5 instead of the 130 main used elsewhere.
And the late 1600 bay-kombi, which came with 125 mains instead of the 130 from 1600 beetle versions. But... that 125 jet was used only in combimation with the 90deg elbow, long ducting and side-mounted aircleaner of the kombi.