Hi lowbeau67
please show a picture of Your gate --- picture taken "opposite direction", picture taken when the ball rolls towards the gate. See the lower right corner of the JPG --- from Your picture "situation: When the ball has rolled through the gate".

Here http://www.planetarypinball.com/mm5/merchant.mvc?Screen=BOOK - I looked through the "Bally 1976 Catalog" --- no drawing found (of the gate). BUT my Williams Shangri La has the same gate --- in the Williams 1969 Catalog on page-37 is a drawing http://www.planetarypinball.com/reference/partsmanuals/WMS_Parts_1969/index.html#/36/ - http://www.planetarypinball.com/reference/partsmanuals/WMS_Parts_1969/index.html#/37/zoomed

See my JPG - when the gate is closed: "my red wire" is down - when a ball rolls onto "my red wire" - the ball is reflected.
Gate opens means "my blue wire" is pulled downwards and so "my red wire" is lifted - ball can roll under - ball rolls through - ball pushes away "my green wire" - as my green wire is affixed to the housing: My green wire is lifted - after the ball has rolled further: Due to gravity my green wire plunges - hindering the ball to roll back into the playfield. We must see a picture "my red wire". Greetings Rolf

0Shangri-La-Gate-01 (resized).jpg

Hi lowbeau67
in the vaults I found these two pictures, greetings Rolf

0Shangri-La-Gate-02 (resized).jpg

0Shangri-La-Gate-03 (resized).JPG

Hi lowbeau67
do not hurry "turn the lever arm on Your pin" --- see the JPG in post-4 - I painted "green" on Shangri-La and on Your pin: The wire that is lifted by the ball roll in - roll through the open gate --- "green" is just to hinder the ball rolling back into the playfield. I believe: "Green" is mounted correct in Your pin --- You must investigate on "RED" - RED must be lifted when "blue" is moved down by the pulling Gate-Relay --- RED must plunge down due to gravitiy when the "blue" is no longer beeing pulled-down. Greetings Rolf

Hi lowbeau67
thanks for the picture - looks good.
Troubleshooting later in the post --- here the story to my Shangri La Gate: See in post-5, first JPG, bottom left corner "12A" --- the old gate-wire did brake exatly there - I had two pieces of the broken wire. See the upper left corner on the JPG --- in the german language this is called a "Mobile" - we may hang such things on the ceiling and air makes the Mobile to turn a bit. I bought wires as used in Mobiles --- tried to make me a new "12A complete from G to 12A to E". Then I found-out: The Mobile-wires are not stiff enough - they bend when a pinball-ball bangs onto the wire. After some time I then was lucky and could buy a replacement "12A complete from G to 12A to E".
See the JPG in post-4 - "my 'drawn blue' wire for to open the gate" --- the old, original "blue I had" did NOT open the gate wide enough (just as in Your pin). I spent hours trying to put washers on top of the posts to raise the whole gate mechanism --- to put washers below the posts to raise - I tried to sneak-in some stripes of cardbord between "wooden playfield and screwed-on Gate-Relay" to vary the distance - so the old, original 'blue wire': "please, please, hopefully will function". NO LUCK.
Then I had the idea: The Mobiles-wire I had bought --- I made me about five "new blue wires - I bent them --- but each of these newly-made five wires was of slightly different length --- I made one and tried it --- I made a second one (a bit different in length) and tried it and again and again - and then the (about fifth) one had the right length --- and since then the Gate on my Shangri La functions.

Troubleshooting: Take away "blue wire" --- manually operate the gate --- does it functions beeing closed ? You then press with an finger on the place the blue wire would pull - You manually press - You manually open the gate - question: Can the ball roll through - can roll under the opened gate-wire ? You then let go on the "blue point" - question: DOES gravity closes the gate ?
And when the gate (maually operated) works without "blue pulling wire": You take Mobiles-wire and make You one, two, three ... "blue pulling wires of different length" --- make wires until You have a wire with exact length. Greetings Rolf