Yeah it’s really bad. Today I sprayed the reflector with hair-fixing spray to give it something like an orange peel. I’ll see tonight if it did help a little bit.
Otherwise I also have a MT-G2 coming from IOS 
Hi ChibiM. Did you measured low kcd reading while using only one battery? Because buck drivers have fairly high resistance by their nature so if you measure 2.4A at the LED when using two batteries, most likely you would only get 1.8 or 2.0A at the LED with one battery, and this kind of phenomenon has been brought up by the others before. This is not an issue actually, but it is just the way they are.
But if you use two batteries and still measure low current at the LED then it must be something else.
If the emitter in your Y3 is just slightly off center I still think it won’t affect the lux reading so much. Did you check if the emitter is sitting deep enough into the reflector?
Just as a reference, my modded HD2010 with dedomed XM-L2 put out 140kcd at 5.0A - it’s not the best example as I know some people can get around 200kcd out of it, but this is sort of an experimental light to me lol. You may want to check the current draw of your Y3, or even better swap in a new and better emitter and see if anything does improve.
Hi, I posted my results a little earlier in this thread. I tried it with 1 and 2 cells. 2 x 26650 and 1x 26650 and also 1x 18650 samsung 25r.
No, the Led doesnt sit inside the reflector, its slightly below.. Thats how I got the highest readings. I used different thicknesses of led centering rings, and got the highest readings when I unscrewed the head slightly, and have gone back and forth, and got the highest readings when the led was slightly below the opening.
I don`t really get very high Amp numbers with 1 cell. I think it was still below 3A with 1 cell. (need to double check I guess) I used 2 short solid copper wires to measure the amps. (those wires are used in houses for main electricity). LINK to similar wires.
ps. I edited the post, to show that I meant 200.000cd and 300.000cd. not 20kcd and 30kcd..
Ok here is the reflector with op and it looks promising ...
... the donut hole is gone!
Now the hotspot is bigger and very diffuse with a smooth transition into spill and some irregularities from the spray.
Mouseover for the standard reflector.
The XHP70/OP combo looks like a good floody light!
My MT-G2 just arrived today, and I couldn't wait to swap it over. Haven't tried it at night yet, but I'm really liking the neutral white of the MT-G2 over the stock bluish XM-L2. Didn't bother to do spring bypasses, since the driver is stock. Swapped the wire with some 22awg only because the stock wire (which I think is 22awg also) was too short to work with after adding a shim. As a bonus,the reflector and lens no longer rattle. 
Wouldn't have been able to do this mod without everyone's knowledge, so thanks!
17mm DD FET, dedomed XM-L2 U3, Efest 35A, Standard lens (non AR), LED focussed, braided springs… 236kcd measured at 6.2 meters, LX1330B. Im impressed…
They changed the driver( again) recently, not with everything modded( spring, resistors est) with a 25r class battery it gives like 3.7 amps ( on an emitter with an Alu PCB)……sadly, we dont have a promo code for it
I wonder if the new driver also supports MT-G2?
Having just gotten around to doing my transplant I'm so impressed with it that I'd like to covert the second one I bought but at higher amps.
I dont see any reason why it would not support an MTG-2 with two cells. Have you an led?
No but I could easily get another from IOS. What I need is a better driver that will drop in. I can do some types of mods but changing surface mount sense resistors is a bit beyond my current skill set or toolkit.
The emitter swap (MT-G2 on Noctigon) I did on the first one was pretty straightforward and produces a very nice wall of light in this unit with the standard driver. Still, there is always a desire for more....... 
I can send you an LED if you like but cant do anything on the mod side of the driver. There just a little bit small for me.
Thanks for the offer Steve but I'm sure you'll have some more worthy works in process that can utilise it. I'm not in any real hurry.
There are still some at $9.90 on 20mm boards at IOS. Shipping seems to have gone up too unfortunately ($9.90) so I might need to see if Hank has anything else I need.
You mean the newer version delivers 3.7A to the LED? That is interesting. Are the modes still the same?
Promo codes still worked for me. $24.99 with code GBYEZL
My latest Y3 mods. Building up 3 fully modded Y3's, with the latest Tiny85 Narsil firmware. Here's what the drivers build up looks like.
Holes drilled out for 18 AWG wires:
Coming off the left back connector of the switch is a jumper to ground. I beefed up the sturdiness of the switch, because these switches are not made or mounted to take some high stress. I added solder on all contact pts of the switch, then build up a nice pile of JB Weld for the ultimate rigid mount:
Few views of the piggyback wight FET+1 driver with the Tiny85 w/bent pins to fit the 13A pads, and the extra 0.1 uF cap that seems required for high amps:
On one of the Y3's, I used a XM-L2 U4 1C on a 20mm SinkPAD, but needed to elevate it, so reflowed it on a 20mm square, 1.0mm thick copper shim:
I did another Y3 with the same exact driver setup, but used a 26 mm MaxToch MCPCB instead. I like the way the 26mm Maxtoch came out, and easier for wiring/mounting/centering, etc. It turned out the one with the Maxtoch MCPCB has a little higher amps, more lumens, better focus and throw. I'm sure it's not all the MCPCB, but, I'm sure there is some connection. Actually on this SinkPAD one, I might remove the screws to see if it helps.
These Y3's with this setup are outstanding for heat mgt and show little drop off in output in the first 30 secs. I got the most amps/output with a new dark purple EFEST 4200 mAh 26650,bought from LiIon Wholesaler, for a pretty good price. I did a bunch of cell tests in the better Y3, and the best #'s were with the EFEST 4200 mAh 26650:
cell @4.22v: 5.30A @the tail, lumens: 1955 @start, 1911 @30 secs, little lower cell at 4.19v: 133 kcd (729 meters) measured at 5 m.
The lumens is the highest I ever measured on a one cell, 1 LED light - think the highest of any one small dye LED light actually. This light has a UCL/p lens, spring bypass's of course, the heavy 18 AWG LED wires, Extreme GC grease on the pill top, NO-OX-ID treatments, etc.
Bravo Tom, i will test your new firmware asap: in Y3 ofc
I have one builded with 26mm FET DD driver and ramp firmware whitch is also good but Yezl look like firmware is better
I am repeating this here maybe 6 months now, its the best 4200ma 26500 battery and maybe the best 26650 in existance considering its high amps/ capacity ratio: its real camacity is arround 4500 btw/ at 5amps consumption
Something that is interesting too:
Same mod as Tom`s , same emitter but dedomed, MT 26mm DTP and DEFAULT Y3 driver with a spring bypass, 120resisttor mod, 20ag wires and same battery: efest 26650 4200 purple:
- It gives 3.2 tail amps at start with a fresh battery and arround 160k mcds
This mod will be good for ppl who dont wanna invest time , effords and money in a new driver
An IMPORTANT info
Lately the default Y3 driver is different: when s. resistor bridged it could give 3.5-3.7amps but it has the habbit to kill the emitter due to its high ripple, so dont do it: i was quite stubborn and killed 4 emitters this way on 3 different light 
Mitko - have you ever has one of those driver mounted switches fail? Didn't happen to me with a Y3 yet, though on one, the button was slightly tilted back. I did a few modded up ZY-T11 clones (https://budgetlightforum.com/t/-/21292, best source now: DX ZY-T11 clone), and basically has the same switch as the Y3, but had a switch fail - got pushed back, tiled off the driver - switch no longer worked. It was an easy fix - just re-soldered the contact, getting it back into proper position - nothing broke fortunately.
It's actually a great, cheap little host - quality of the host is so-so, but I got a 26 mm Maxtoch MCPCB in there, UCL/p lens, FET+1 driver with Narsil firmware on a Tiny85, can handle high amps surprisingly well. Nice pocketable EDC with extra throw because of the wider reflector. It has a tail lockout w/anodized tailcap threads, but it will wear off with usage, so the lockout can develop flakiness. That's why the UI lockout feature is nice with this light.
From now on, I'm gonna use the JB Weld on those ZY-T11 clones as well, and any other lights with similar switch's I work on.
Yeah i had 2 unfortunately, the first i think i damaged myself while cleaning the PCB with a hot air but the second one just died as the flashlight was never modded….well, s$$ts happens Tom, yet i have many of those drivers as spares cause i also mod Yezl as a hunting viechle observation torsh : with a cable and 12v power source - so i remove the driver and the tail assembly
I actualy look for a Yezl Y3 clone but better- lately they changed even reflectors, now when you press them harder to the MCPCB its shrinks and as you said before they always have minor “chips” here and there, other type of issues….
Somethgn like a 2010 but with 2 buttons…a better quality Yezl
I have not been around BLF for quite some times already, and didn’t realize that the XM-L2 U4 1C can produce 1900+ lumens at only 5.30A?! What did I miss so far? 