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Discussion Starter #1 (Edited)
Hey Guys:

I bought some new 35 mm venturis from Pierce Manifolds for my Spider. I've been using 32 mm for several years but Enrique won't let me pass and I'm seeing John M too close in the WINK. (Objects in Mirrors may not be as close as they appear.) Never the less, I want to vent this engine with 35mm vents so what is a good E-tube setup- Where do I start. The Head is a old Sperry completely ported and polished unit with large valves. I believe the pistons are 10.1 :1. The manifold is the Series two cast iron into a stock exhaust.

Please give me a guide for purchasing some Emulsion tubes, Main and Air jets.

I have a bunch of E-tube set stached away somewhere and I'll pull those out and add them to the post so youwill know what I have available.

EXTRA SET F-11 TUBES
EXTRA SET F-16 TUBES
EXTRA SET OF F-34 TUBES

CAN YOU GUYS WORK WITH THESE?


Thanks for the help.

Bud Feigel
Lexington, Kentucky
 

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The rule of thumb on main jets is go up 10 for a 2mm increase in venturi. So if you have 130's now you should try 145's. You may not have to change emulsion tubes. I would try to get the main jets right first then see if you need to change air jets or idle jets. There is a possibility that you will not have to change them.
 

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Discussion Starter #4
Wow! The 35mm venturis really put a happy face on that engine. Thanks Ed for thr advice. I used 1.25 Fuel Jets and 235 Air Jets in the F-11 Emulsion tubes. Maybe this early Sunday Morning I can do a plug cut to see if I need to lean it any more. There still might be some more power there.

Bud Feigel
LExington, Kentucky
 

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I'll say there will be more power in there! But I'd wager it's already too lean. General rule is the mains should be about 4 times the venturi size as a starting point. In this case, 140 (which is in there with what Ed said). Air jets, for a starting point, can be the mains plus 50 (or 190 to start with).
 

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Discussion Starter #6 (Edited)
Ok Guys.......Something else is wrong.........

The gas gauge must be going bad. It keeps going toward EEEEEEEE.....


but I like it!!!!!
:eek:
 

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One of the nice things about Weber main jets is the adjustments are so coarse that it is usually easy to sense the difference when you make a change. Same goes for idle jets. I am thinking of making a set that are half way between 55F17 and 55F21 for my emissions carbs. You should be able to notice a difference between 140 and 145 mains, assuming that they are close to optimal. All bets are off if they are both grossly lean or rich, but that should not be the case for you.
 
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