My outer cover doesn't like me - 4 speed AMC Gearbox

Top is top :)

You can work this out from how the gear lever moves the pawl - lift the lever up and the pawl moves down. To put in 2nd, use a screwdriver to move the roller end of the quadrant down to 1st, then up thru neutral and into 2nd.

If, with the outer cover in place, you can only select gears in one direction then you need to fiddle with the gearchange ratchet spring - which will be covered by Mick somewhere.

The camplate is correctly timed when the quadrant arm is aligned with a gearbox stud in 4th - again Mick will have covered this, it's also in the workshop and Haynes manuals.

Sounds like its working perfectly. A small clearance both sides allows the pawl to move freely in both directions ,as it needs to. 

... it's a shame that this box is called the AMC one as it's about 90% Norton from before the AMC takeover and much of the internals date back to the early 50s if not even pre-war.

AMC bikes (Matchless and AJS) were using the horrible Burman boxes up till the mid 1950s.

It sounds as if the pawl is only picking up in one direction. In use, I've known this be caused by a greenstick fracture of either the pawl spring or the gear lever return spring. On the Commandos, there is also a thin washer which has to sit on the correct side. It takes very little to stop this simple but ingenious mechanism from working.

The purpose of the spring is to tip the pawl over so it engages with the ratchet in the direction you want it to move. "Fiddling" with it means bending the spring so that it doesn't quite touch the pawl at rest but the pawl flips as required as it comes into contact with the spring when the gear lever is operated. Ideally the pawl will sit so its tips are equidistant from the ratchet when at rest. You can do this with outer cover in your hand but it can take a couple of attempt to get 'just right', Hemmings must have gone over this in his videos.

Richard  has described a couple of common issues that are not easy to spot , An almost invisible hairline  part fracture of the gear lever return spring can take its power away in one direction . And the large "pen" steel washer is easily missplaced to jam the action. The two small bolts that hold the change mechanism to the cover have a small amount of tollerance that can be used . There has been some poor pattern springs sold ,I had to reject 3 out of 4 that i had accumulated.

I don't think anyone has mentioned this but in Mick Hemmings AMC gearbox rebuilding notes, he stresses that the hairpin spring for the ratchet pawls must be fitted the correct way round.

"Fit gearchange hairpin spring with the straight leg uppermost (pic 61). If you fit this the wrong way round, you won't be able to select the gears."