View single post by Jim Ketcham
 Posted: 01-25-2015 04:21 pm
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Jim Ketcham


Joined: 03-13-2005
Location: Salt Point, New York USA
Posts: 195
This is covered quite extensively in some earlier posts. Tim Engels post is a wealth of info on Dellorto jetting. I have a very similar engine config as you do so I'll post what works for me. I've found that idle jetting makes the biggest difference.

Main jet 155 (132)-----160
air corr jet 175 (220)-----230
Main emulsion tube 7772.11 (7772.10)------7772.8
Idlejet 50 ( 56)------58
Idlejet holder 7850.1------same
pumpjet 50 (35)-------same
starter jet 70 ( 80)------same
starter jet emulsion tube 7482.1 ( 7482.3)-----same
Chockes 36 mm------same

I've used this jetting in two 2.2 conversions with very similar specs as yours. My only difference is 107 cams.

John Kimborough has written up a very straight forward tuning guide for the Dellortos that I believe works quite well. It can be found in an earlier post or at least a link to it.

I have found that a good indicator of a inlet manifold leak is lack of response to adjustment of the mixture screws. I recall that on my carbs adjustment range is within 3 turns from seated.
Of concern is your need to make 5-6 turns on the air bypass screws to match barrels. I've only had to make minor tweaks to the air bypass to match barrels. This strongly suggests a possible intake air leak so I would concentrate there. Of course, an inlet manifold leak makes tuning impossible.
Good luck,