Ok.. thinking out loud again.. In order to get the bike to run with that snorkel ( and lid? )
you have to have a "biggy" MAJ in order to produce the desired pressure gradient for the desired emulsion in all situations where the needle is unseated. This delicate balance between the MJ and MAJ goes all to hell when you pull the lid. Lidless, you now have a huge MAJ providing huge amounts of air to the emulsion - causing leanness ... And this leanness (imbalance really) cannot be cured by simply throwing in larger main jets and raising needle heights - as I have done .... The desired AFR must be achieved by establishing a "new" balance between MJ and MAJ ...
Now, about the latest chart with 136/5N:
This explains why the AFR's stay lean with the DGR... The increased signal to the carb causes an exacerbation of the totally discombobulated MJ/MAJ tap dance.. This also explains the lean upper end with the FMF system - at those RPMs the signal, once again, to the carb is strongest and too much air flows into the emulsion tube through that damned biggy MAJ... 5N is the key, it fully exposes the flawed MJ/MAJ balance.

So, if I have this understood correctly, It's time to roll up our sleeves.. I bet 132/5N with proper MAJ re-sizing will scream, AND , 136/5N with a well re-sized MAJ will Scream+... (near sea level with lid off and a good slip-on...)

 

Klxster,
About that frothy fuel. I think the mj/maj “balance” as you named it, is the purpose of those jets. The frothy fuel is but a side affect of the process. I like that side affect.

Now, that emulsion tube thing. I switched the stock tube for a 13091-1985. Same number of holes but the top 3 rows are drilled about one row “higher” than stock. The mixture seems a little richer right off idle, everywhere else I cant tell the difference between the two. I think the frothing starts sooner and that froth is easier to suck out into the air stream. Also, it would possible to produce an overly lean off idle condition if the float height was set too low, thus exposing the top row of holes to the air above the fuel level in the air chamber which surrounds the emulsion tube. I think mikuni or dellorto call that tube the “Emulsion tube”.

I will solder two of the top holes closed and drill two new holes below the 3rd row when the cast comes off my right hand.

 

Problem I have is that the HP/TRQ I have now is so new that I'm not sure I can sense another HP (or maybe even 2) up high with the FMF system in place.

 

Looks like I have to gear up for a whole nuther series of experiments to gauge the effects of MAJ tweaking...

With the DGR on, I could start tweaking the MAJ as is - that setup could use more fuel everywhere - and should produce dramatic enough TRQ increases for my to seat-o-pants dyno to sense..

 

Great little mod Dave; very perceptive.

I don't recall my CVK's a/f needing correcting with an air jet tweak, and I'm not running it anymore on my 250 anyway. Tuning with maj size applies to the pumper carbs as well though.

IIRC my TM36 as supplied from the vendor with no air jet in it, tended to go rich-er as the rpms climbed. Fixing that would require redoing the mj and maybe more if I added a maj. It's ok for now

 

Ok, did a MAJ mod on my bike and went for test ride with the DGR.. Results are inconclusive because it's so damned powerful that I don't think I can tell another HP or two or another Lb Ft of TRQ or two. The AFR must be richer at Needle RPMs as well as transitions on either end of Needle RPMs.. I'm sure the bike runs stronger - it's just too new a power band for me to give a definitive assessment... It spins the rear tire way too much off road for me to get a good reading..On pavement - It hits the 10.5K ignition cutoff seemingly instantly with a snap to WOT at anything above 6K.. WOT in first, shift to second and instantly snap back to WOT will lift the front tire if I'm not sitting all the way forward. It's crazy fun..
Details: The stock MAJ is .1" . I rigged my old stock main jet (Which I have no need for..) as a MAJ with a .05" orifice.. My research indicates the CV requires a 1psi difference between the ambient air pressure that is above the fuel in the bowl, and the air pressure that has flowed past the MAJ and is entering the emulsion tube. The snorkel practically creates this differential in the airbox - thus the MAJ is a whopping .1" ... I have no idea what will restore the proper balance of MAJ air and MJ fuel in the emulsion tube running with lid off, but I guessed cutting the MAJ size in half would be a place to start.

 

Since this mod is a little involved, I guess it'll have to prove its' worth on the dyno.. From, what I've read, go too small with the MAJ and fuel atomization will suffer and performance will not improve..

 

Boatdriver has completed an initial ride using 136/5n. He reports fantastic results. This is a game changer because he is running standard Cam timings. More to come..

 

Brought the bike out to the Ranch for further evaluation...

My MAJ mod was probably not very functional.. Turns out the stock MAJ is a jet with a .1" opening that tapers to something very small.. All I actually did was to reduce that .1" opening to .05" ... I have removed the mod..

The DGR and FMF system continue to perform as the charts show. On the road, the FMF is the only way to go as it pulls so hard in the upper RPM ranges.. Each WOT gear shift keeps the engine in the FMF's sweet spot - so it just keeps pulling hard after every shift..
On the road, the DGR requires short shifting ( @8.5k ) - but the HP available at these higher RPMs is, of course, less than with FMFs'... It simply doesn't give the same pull when running through the gears @ WOT as the FMF. Also, top speed is probably less with the DGR.

Off road is purely owners choice - I ride fast and would keep the FMF.. If I was taking a gal on back to the trails and then putting around offroad , the DGR is the only way to go- it makes up to 2hp more over the FMF below 6.5k and that is a big TRQ difference. The TRQ @4.9k would take 6.5k with the FMF..

There is probably much more power to be found with the DGR - AFR's are still too lean for it to show its' true potential..
There is probably some power to be found up high with the FMF -AFR's are still too lean up high for best power..

It seems that every portion of the AFR curves that are above 13:1 are costing power. Unfortunately there is a lot of "above 13:1" still..

 

My MAJ mod was probably not very functional.. Turns out the stock MAJ is a jet with a .1" opening that tapers to something very small.. All I actually did was to reduce that .1" opening to .05" ... I have removed the mod..

Since I'm looking at doing something similar to my Keihin I'll reopen this old MAJ mod subject and ask why you didn't go to a smaller MAJ after finding out the inner passageway was smaller than the part that's visible?

On my particular Keihin the part that's sticking out into the air stream at the bottom of the carb inlet barely accepts a 2mm drill bit, but the inner passage is much smaller; only allowing jet a cleaning rod to slip all the way up to the needle jet. It'd seem though that eventually going small enough with a MAJ would at some point begin to restrict MAJ inlet air and yield a richer high rpm mix.

I have to go out once the weather clears and check the WOT a/f numbers to see if the reading drifts rich or lean at high rpm