View single post by Brian Kelly
 Posted: 05-23-2005 02:54 pm
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Brian Kelly


Joined: 03-22-2005
Posts: 43

A couple of things. I’m running 45’s and by no means am an expert.  But I can share some of my experience.

Idle holder size 7850.# (# = Lean- 5,10,9,4,1,3,6,7,2,8, -Rich). You’ve gone from .5 (lean) to .7 (richer – but a good choice) so now you’ll need to reduce your idle jets which makes sense (black plugs) to lean out the mix. You may have noticed that the .7 has smaller dia cross drilled holes.  These holes allow air into the mix – smaller holes, less air, richer mix.

Also, JAE sells a Lotus part – an anti-popping valve (not sure of the name) that goes in between the carb and the manifold.  They’re not too expensive and in my case eliminated the popping.

I use a Morgan CarbTune to balance mine.  If you’re serious about using these carbs you’re going to need a better tool for balancing.  The uni-sync won’t do the job since it restricts the air flow into the carb. With the Morgan or a 4 tube mercury manometer you can read the vacuum on all 4 cylinders at once and be able to compare.

To adjust the needles pull two plug wires and adjust needles on one carb at a time for highest engine idle.  Then reverse and adjust the other carb.

Also, one by-pass screw on each carb should be closed and the other opened just enough to balance the two barrels to each other.  Once you have the two barrels one each carb balanced to each other then use the balancing screw between the carbs to balance the carbs to each other.  I hope this makes sense.