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Thank you Lare for the perspective, especially we have the same model and year. It will take a very long time for my A4 to accumulate 35000 kilometers, so I think I can safely say I am good for a while

Scotch, I'm thinking we would go back to what you suggest with my bike. I think it's a good opportunity to do some testing, since we will have a sort of blank slate with my new engine. I will start it with not modified original carburetor set. In the meantime, I will put together the spare set and do this modification, and then swap them and compare.
Would be interesting to see how many cranks it takes for each.
For the second stage we'll need patience, until the original setup would start misbehaving. Swapping then and having an instant 'fix' would be the best confirmation that this mod is a problem solving one. But that sort of you already confirmed, and I can't think of any one reason why shouldn't it be done on any engine, new or old. I have a feeling I will end up making this change to my first carb set as well.

Looking forward to LareNurminen results as well!

I think a BIG part of the problem is the camshafts. I have 6 sets of intake and exhaust camshafts and I've measures all of them. Back in November 2017 I wrote in my rebuild post
"2nd - Fix the sloppy duration. The current duration of the cams greater than .005" lift (which is the point where the valve is open, is 170 - 180 degrees cam rotation which is 340 - 360 degrees of crankshaft related duration. All 6 of the intake cams I have dialed, indicate this phenomenon. I can't explain it only tell you what I've found. I'm not in a position to measure the actual opening time and closing time of the valves relative to crank position since that would require reassembling the engine. At this point I'm confident that what I've measured is correct. Possibly Kawasaki felt that having the valves off of the seat by maybe up to .010" had little consequence on actual "valve timing" and designed this into their grind spec. or maybe back in the day when they designed the cam profile and then transferred that info over to the master for the cam grinder, something went wrong. The end result is that what I've measured is faulty and I wanted to fix it if I'm going to go through this exercise."

Having both exhaust and intake valves open for 340-360 degrees of crank rotation at starting rpm will really not the stuffing out of the possible intake vacuum at cranking speed. Have you ever heard a big block V8 with a 290 duration cam rumbling at 900 rpm? Don't leave a cup of coffee on the dash. You'll wear it ! Now try to imagine what would happen if the duration was up to 340 degrees. Thee only way you'd get it to start would be to spin it up at 2000 rpm and keep it there for an idle speed.

I'm still struggling to make up my own cam grinder. I've tried 3 different setups and not happy yet. I'm currently working on my "next version"

What would be interesting to find out is what the available vacuum is at cranking speed. Anyone care to throw on a vacuum gauge, leave the choke off, disconnect the ignition and spin the engine over and measure the intake vacuum??

This reminds me Kawboy of the cam chain which I haven't replaced with a new one. So, my 'new' engine is not exactly new. If you remember the photos I posted, I aligned the dots and counted links so the timing is set correctly, but the position of the dots couldn't be placed perfectly. Which you will be able to do with your adjustable cams! I am sure the degrees on my engine are not a perfect number as per manual, and most engines will vary as well with use. I will see how mine behaves, and of course everyone will know.

Anyone care to throw on a vacuum gauge, leave the choke off, disconnect the ignition and spin the engine over and measure the intake vacuum??

I can do this; maybe as soon as today.

Lets NOT turn this simple query into a 20 page thread of semantics over engine oil weight, oil-temperature, oil-level, battery type/cranking amps, compression, etc, plus the type and style of vacuum-gauge used or the "Point" will be rendered useless before it can be made

Engine Vacuum at "Start Turn-Over" is "just" under 3" HG, on mine. Kawboys speculation about this with respect to the valve duration's seems logical and is probably correct given the best I can get (have ever been able to achieve on any set I've rebuilt) for the synchronization, averages 9" Hg !
Keeping in mind some #'s I posted regarding the enrichment diaphragm: Starts to close at 10"Hg., 1/4 closed @ 15", 1/2 closed at 18" and closed @22"Hg, it makes sense.

Thanks for doing that Scotch. That's all I need to know. Thank God that we're trying to pull gasoline up from the float bowl and not mercury. The mercury wouldn't make it to the enrichment circuit at the top of the carb.
Back in the day when I was working as a auto mechanic 1974-1980 a lot of the boys with souped up cars ran vacuum gauges. When we used to flip these cars over on the starter you usually saw 8-10 " HG and about 14-16" HG at idle with a mild cam in the 270-280 duration. A stock car (family car) with a stock cam in the 240-250 duration would idle around 18-22" HG. I bet you that if you sucked on the end of the vacuum scale with your mouth, you could draw down to 7" HG.