Given the number of variables involved (bucket to ears, lens to rim, beam direction screw), is there a straightforward way of adjusting the beam on the US headlights? Also, what should the finishing positions be of the various items on the long alignment screw?

I am thinking that if the bucket and lens are all buttoned up tight and the light fitted into the bucket, then the adjusting screw will effectively be locked in place.

Sorry if I'm missing anything obvious!

My adjusting screw head was stripped, so I just removed it and the spring , and tightened the two screws that the headlight pivot on. Now if I need to adjust it side to side, I can just push on either side of the lens with my thumb to adjust, and it will stay in place. I don't ride the old CT-1 at night anyway, so it's really only for daytime use. In California you're supposed to have headlights on during daytime riding.

Lens adjustment is side to side on pivots.
Up/down are ear bolts on sides.

cliff

"Lens adjustment is side to side on pivots.
Up/down are ear bolts on sides."

Thanks.

What I'm not understanding is how to do any adjustment with the headlight in position, if all of the mounting nuts and bolts are tightened up.

I don't see how you could make other than very minor adjustments to  the side to side after it is buttoned up. I didn't realize what was going on inside and just started unscrewing the adjustment screw to take the headlight apart.  I soon realized this was not going to work, but not before I smashed that white plastic collar above the two locked nuts.  l  ordered  a new collar and got the wrong part, still waiting on the screw.   

The headlight bulb is physically attached to the chrome trim ring, with the trim ring secured to the painted headlight bucket. Side to side movement is still able to be done with the headlight secured to the bucket since it's attached to the trim ring and not the bucket. Up and down is done by simply moving the headlight bucket up or down on the ears. Even with the bucket tightened to the ears it'll still move up and down with a bit of force being applied.
 

There's a spring opposite the bolt shown in the pic above. The spring applies tension across to the bolt side holding it tight in the trim ring.

The headlight is attached to the chrome rim with the screws on top and bottom, and as long as you don't crank those down super tight, it can still pivot it side to side with that long adjustment screw. The spring on the side opposite of the long adjustment screw keeps it from flopping around.

As I posted earlier, my adjustment screw head stripped, so I just removed it and the spring and tightened down the pivot screws. Now it stays in place on its own and I can still pivot it with my thumbs just by pushing on the left or right side of the bulb.

Thanks.

My lens/bulb is bolted tight to the rim, which is bolted to the bucket and therefore I can get no lateral movement (ie the adjusting screw can't turn). Also, how on earth can you lock the adjusting screw in place from the outside, or do you have to take the lens/bulb out each time you want to adjust it?

I am dealing with headlights without the extra inner ring - ie RT2, not DT360A.

"The headlight is attached to the chrome rim with the screws on top and bottom, and as long as you don't crank those down super tight, it can still pivot it side to side with that long adjustment screw. The spring on the side opposite of the long adjustment screw keeps it from flopping around."

Thanks.

So are we saying that the retaining bolts shouldn't be fully tightened?

I'm still not sure of the final resting places of all of the parts on the adjustment screw! 

I'm not sure what you mean by retaining bolts. We might be talking about different headlights, I'm referring to the CT1 headlight. The bulb is only secured to the chrome rim with two screws on the top and bottom, so it can pivot. Unless you really crank down on those top and bottom screws, you should be able to adjust it side to side with that long adjustment screw. However over the years that screw gets difficult to turn, which is probably why the head on mine was stripped. As you can see in these pictures, I just decided to take that adjustment screw out, and removed the spring from the other side, then tightened down the pivot screws and nuts so the headlight will stay in place on its own. But can still be pivoted side to side by just pushing on the front of the lens on the left or right.