Vintage BMW Motorcycle Owners

The bike came with a side car ratio final drive and I'm now (at last) installing the last purchase from Mark Huggett, a new 35:9 gear set.
Helped by Jan Withagen's excellent video (https://www.youtube.com/watch?v=1dBh7WkNVGQ), I'm pretty close to all the factory specs, but still, when I turn the sprocket of the driving dog, by hand, I get a noise that increase when turning faster.
And because I went very close to BMW's specs, that is what drives me crazy. Worked late into the night with no success.
Other than that everything works smoothly. Needless to say, all the bearings are new.
My only question is where should I add or subtract Shims in such a situation:
On the outer cover that accepts the drive dog?
On the pressure bronze ring on the drive dog?
Where is that noise coming from anyway?

Can you describe the noise? Maybe even a youtube video? Are you sure it is not just normal gears whining? Back in the old days those gears where lapped together, I don't know if the new ones are quite as well produced.

And you think you have the lash and engagement of the gears correct by shimming, I assume.
The easiest way to check the engagement of the ring and pinion gear, is go buy yourself a tube of cheap bright red lipstick.

Remove the cover.
Smear lipstick on 3 or 4 of the ring gear teeth, on both sides of each tooth. Then take a butane mini torch, and holding the flame well back from the lipstick, wave the flame at the teeth. You will find the lipstick will melt and spread out in thin layer completely covering both sides of each tooth. Then, while spinning the pinion shaft in the direction it turns, (I use a piece of radiator hose, clamped down on a 3/8 drive mounted in a battery drill) and use your other hand to press down on the bearing race on the ring gear shaft that goes in the cover. Spin it with the drill, and then remove the ring gear and look at the engagement pattern.
The lipstick will transfer onto the pinion gears, and you will see clearly where the teeth are engaging. You should have an oval engagement pattern, in the center of the tooth. If the shimming is wrong, it will not be oval or in the center of the tooth on both sets of gears.

Thank you very much.
As always , simple, great info.

Seek and Vech,
Came back to report.
All went well with the lipstick trick, Vech. The gears were spot on, I had to shim the pinion a little from the drive shaft side and that's it.
Another strange (new) noise came from the rubber boot that encloses the bell cover. A little grease solved that too.
Seek, the gear set was purchased from Mark Huggett, and you are probably right regarding the lapping in as now while riding, I am accompanied by a kind of non-obtrusive, even pleasant (?) hum of the new gears. I guess that will go away with time too.