V3 Box. Full Auto Is Fine. Needs Multiple Trigger Pulls on Semi. Update)

[Asomodai]

Odd one here. 

This is my JG SL8 DMR that has flummoxed multiple techs for being really loud gearbox wise. Changing out the original box for an SRC as the old one is warped. 

Installed some SLD Advanced gears but it does not work well with the SRC gearbox as they appear to be binding. Even when all shims are removed and some of the side of the gearbox dremeled down where the built in delayer was rubbing on tappet guide rail. It wouldn't cycle on full auto or semi.

Switched out the SLD gears for original SRC gears. Full auto seems fine, but semi has the same problem as the SLD gears did where you need multiple pulls of the trigger on Semi auto to equate to one shot. 

Tappet and nozzle is not rubbing on anything. 

All parts are pretty much unused. Any ideas?

 

[Asomodai]

Did a little bit more work on this. I filed the edge of the cut off lever a little bit. Which helped slightly, but I think it is a worn second trigger (The Zinc part that is assembled with the trigger and trigger spring.) There is a small chunk out the top of it. What do you guys think?

Cheers!

View attachment 58498

 

[Adolf Hamster]

so the motor is trying to shift it on each trigger pull but it's cutting out early?

 

[Asomodai]

so the motor is trying to shift it on each trigger pull but it's cutting out early?

Click to shrink...

Yes. Hence why I think its trigger trolley/cutoff/safety block related. Trigger trolley isn't being pushed forward for long enough before resetting. 

 

[Adolf Hamster]

Yes. Hence why I think its trigger trolley/cutoff/safety block related. Trigger trolley isn't being pushed forward for long enough before resetting. 

Click to shrink...

its a tricky one.

the issue i've experienced is using a mosfet with an active brake tends to halt the box nicely in that region where the trigger locks up, but that's not what's happening here.

sounds kind of similar to what was going on with my f2000 for years, but that's a totally different mech and the semi can drop out without the box cycling. i eventually solved that the expensive way by dropping in a warfet and setting up the precocking.

 

[Sitting Duck]

Bit hard to see in brief video but it looks like COL does not fully drop down 101% in semi

so the trolley's "lug" does not slip fully over it

(edit, not under, trolley's "lug"  passes over the COL in semi, which then lifts to pop trolley etc...)

which "should" create a dead zone where the trolley/trigger is impeded from moving correctly

(where we have to briefly switch to auto, fire then back to semi to clear this trigger lock etc...)

NOW - it doesn't quite seem to be impeding the two part trigger like on say a M4 v2 box in dead zone

but that COL seems to have a gap at the bottom, not sitting at it lowest possible point

Which might be guiding the trolley to rise up on travel and jump off

What is causing that COL to sit a little higher ???

two things to check

1 - the switch unit itself is properly seated in the box

they can tend to jump out of position as you close box as not fixed like v2 switches with tiny screw

so that switch "might" have jumped out of situ, causing it to sit higher which in turn is lifting COL rest position

2 - the sector gear, specifically the cam, the whole cam could be keeping the COL raised slightly at rest

I'm talking about the 75% non contact area being a bit larger diameter, that makes faint contact with COL all the time

meaning COL rest position is lifted slightly at all times

In reality this is rare but had some compatibility issues with sectors especially how they sit & operate the COL

Also as time goes on, the alloy JG COL will wear at the contact point and the COL should drop as well as fail to lift 101%

I'm tending to think that the electric 2-part switch is worth a look, if it shifted slightly, then that assembly could/might

throw the COL's resting point out of whack

That COL should drop down flush with box window imho - or as near as damn it so it allows the trolley to pass over it 101%

in fact the trolley on a v3 actually seems to move forward and very slightly downwards as it makes contact with prongs

(well from what I've noticed when checking stuff out in switch/trolley operation)

The other issue is compatibility, it appears to be a JG box, so presume the switch/COL is still all stock

(just checking the switch & stuff wasn't from another box or two and potential compatibility issues)

But yeah, just checked a JG v3 and the COL should be nigh on fully dropped down

(it appears to be lifted on your clip, but having to tip my head upside down like watching Aussie TV)

I'd check switch assembly is located correctly....

close the box without sector gear to see if COL resting position alters

then add sector gear, if COL becomes lifted, then try another sector gear or something

Something, somehow/somewhere is making the COL sit slightly higher at rest/semi

and in turn letting trolley jump off as it engages the contact prongs

I could be wrong, but that is what I noticed from short Aussie clip

edit: just noticed it is now a SRC v3, hence being silver not black jg v3 like mine

ahhh - so this might down to compatibility on SRC & JG bits n bobs = COL sitting slightly raised at rest

yeah - that makes a bit of sense now...

so you might have to rumage around and try the SRC COL or SRC switch or mix/match with JG bits

but the COL imho needs to sit almost touching the bottom of window at rest, not slightly raised

or go back to JG box or something if it still a bitch

if you get stuck or modded bits to fuck and no joy them pm me for JG box/trigger bits

 

[Asomodai]

Cheers for the advice fellas. I pratted around some more with both of my cutoff levers being dremelled to no avail. I didnt have another second trigger which I felt was the problem. Along with the gears being very tight with the SRC box I decided to purchase a quality gearbox to work on. Considering this is a DMR I do need a fairly good gearbox. 

My tech heard of my predicament and gave me a brand new G&G V3 box, G&G Cut off Lever, new Second trigger and a new G&G Trigger switch all FOC. The quality is like night and day. No comparison. 

I put it all together, I think the shimming is a little tight. Do you think it sounds ok? Either way it does cycle all the way. As it's a DMR I am unsure if this shimming is good enough. Video is using an 11.1v lipo in Storage mode. 

 

[Sitting Duck]

Hard to tell with 5 semi shots & even with headphones on

a tiny bit shrilly but not the usual high pitched shrill you usually get

(yes it is running slower with a m120/m130 say but the 11.1v should counter that a bit)

So it sounds OK to me, still better than a number of stock guns

(and some bad builds)

See how it runs, how warm it gets & what amp draw is on say a 4 sec auto burst

should be around 10~15amps tops, depending on motor used

if you have locked it to semi then it is just a matter of shorting or adding a switch to 2 thin wires to fire on auto

(in case modded selector plate or something)

you "might" have a compatibility issue on JG COL/selector plate & G&G bits...

I would have used the JG COL & selector plate as the JG COL is different on G36 & SIG's compared to JG AK's

(and other v3 stuff, maybe the G&G box)

see here:







and the JG G36 selector is cut slightly different to match the smaller lug on silver JG COL

Cyma G36's have a selector which is cut lower the match the more common COL with larger lug

(like the black steel SHS COL shown in post, ffs more compatible bollox issues)

Yet the odd thing is the blue SHS G36 selector plate is more JG compatible than Cyma

the Cyma G36 selector:

https://www.begadi.com/tuning-internals/aeg-rifles/selector-plates/begadi-g36-selector-plate-transparent.html

note how little material is where the semi/auto "ramp" is, especially at semi position

it is just the rail guide on semi with nowt more due to big lug on COL for Cyma G36's

(soz it is upside and facing downwards, but look at low end of ramp & compare & you get the pic)

yet the JG/SHS has more material at the selector plate semi position due to stubby lug on JG COL

Think G&G uses "normal" v3 COL like black SHS larger lug...

https://shop.evosports.com/gg-reinforced-cut-off-lever-for-v-iii-rk

which might raise the COL is semi if using JG G36 selector plate - arrrggghhhh

so you "might" need to use the JG COL, mod the old JG G36 selector plate or buy say another selector plate

If you got a G&G G36 complete box with matching G36 selector then you "should" be OK

(if it all fits in the JG receiver without too much modding)

I have no fucking idea why JG went with a stubby COL for G36 & SIG's

I think they use a regular v3 COL on AK's though but don't quote me as not rebuilt my JG AK yet

But fuck me sideways these JG's can be qwirky on COL/selector stuff

so need to triple check stuff a bit - which if modding for semi only won't be too bad on DMR

if have to pop box open to check/change COL then check motor height in top half of box

with bevel gear & motor in frame to see just close to perfect the bevel is sitting and meshing etc...

then if all ok see if motor cage slightly loose, if you slightly wiggle the motor cage if any shrill reduces

(sometimes a bit of paper placed between the cage/box will slightly skew the pinion to mesh smoother with bevel

sometimes a piece of paper or very thin card placed at rear, tilting motor slightly clockwise will reduce shrill

(you haven't got much wiggle room to work with, but can make a difference on shrilly builds if all else is correct)

despite all this bollox, I still prefer v3's over v2's - but they are both are PITA due to compatibility issues at times

best of luck & well done so far