G&G L85a2 semi auto issue

[beastmode]

I have a G&G L85 with a 13 tooth piston so it's not the old 19 tooth piston ones. I'm having issues on semi auto where I can only fire a few shots and then it locks up, so I have to use full auto and go easy on the trigger all the time. Anyone have any experience of how to rectify this issue? Cheers

[TheGrover]

okay, a few potential causes off the top of my head:

 

• are you releasing the trigger too early, leaving the 'box parked with the cut-off lever depressed? if it works fine in auto, this is what is most common
• could the tappet or selector mechanism be interfering with any wires or connectors?

Thinking about it, its probably the first one, ive done it myself more than a few times in heated situations when forced to use semi. Basically, the way that Semi works is that there is a small lever in the gearbox that is pressed by one of the gears at the same point in every cycle. Unless the gun is on full auto, this lever disconnects the main power until the trigger is released. now, if the motor is cut off early by releasing the trigger and the gear happens to stop in this position, the power will be cut to the motor by this lever, though it can easily be bypassed by switching to full auto where the cut-off switch/lever is not used.

[geoffreym]

combination of the above "releasing the trigger too quickly/not letting it finish it's cycle" and having a lower powered battery/motor.

what battery are you using?

[beastmode]

I tested it out by pressing the trigger in fully each time and it seems to be working ok now. Suppose I've just got remember to press all the way in with this gun. I'm using a 7.4 lipo. But had the same problem on 9.6 nimh. I think I'll upgrade the motor soon anyway.

[Sitting Duck]

I have a G&G L85 with a 13 tooth piston so it's not the old 19 tooth piston ones. I'm having issues on semi auto where I can only fire a few shots and then it locks up, so I have to use full auto and go easy on the trigger all the time. Anyone have any experience of how to rectify this issue? Cheers

 

is it the original 19 tooth sector with say teeth removed ???

 

Forgive me but going by the Army R85 being a clone of it, then if original sector gear then it is very likely still gonna pre-cock

or cut-off lever being activated mid stroke as opposed to the usual straight after piston is released...

 

Now a SR25 SECTOR gear may - and I say may work as it is 19 teeth also but the cut off cam is directly after piston release

BUT - I haven't really messed with my R85's yet - but was one of things I was thinking about....

Deffo the R85 spur is a bit weird and is different to "normal" stock gear sets

(I was messing about with a SHS R85 gear set in a v2 box but all gears didn't mesh correctly & seemed like spur was not meshing - could be a higher ratio than a stock 18:1 but whatever - it didn't work properly)

 

However the SR25 & L85 sector's do "appear" similar 19 teeth (not tried the SVD AEG 19 teeth)

so if they did work then the difference would be L85 or R85 has the pre-cocking & SR25 does not

 

The pre cocking on 85's was always a bit hit n miss - maybe ask Sp00n - he has done some work on G&G's & has a R85 spare box I think

soz to drop him in it but I got a hunch that a SR25 sector might be worth trying in L85's to eradicate the semi lock up's perhaps

before people go down the usual 15 tooth piston & spacer route - again I not tried it yet but sounds to me if still using a short stroke R85 sector

then that poxy pre-cocking position might be part of reason still why semi lockups still happen

 

If you have 13 tooth - very short stroke piston btw - most go for convential 15teeth normal aeg piston

and aprox 9mm/10mm spacer behind piston to make up for missing 3 x 3mm teeth)

then you may be able use a "normal" M4 sector with a couple of teeth removed

 

if your sector is a normal M4 one then it should not happen coz it won't pre-cock no more

 

Again - this is my understanding of L85 or R85 problems but like I said I haven't ripped my boxes open just yet

so take all this crap with a pinch of salt - it is just my theory/understanding of it so far

 

best ask Sp00n or others with real hands on experience of G&G L85's....

[sp00n]

 

is it the original 19 tooth sector with say teeth removed ???

 

Forgive me but going by the Army R85 being a clone of it, then if original sector gear then it is very likely still gonna pre-cock

or cut-off lever being activated mid stroke as opposed to the usual straight after piston is released...

 

Now a SR25 SECTOR gear may - and I say may work as it is 19 teeth also but the cut off cam is directly after piston release

BUT - I haven't really messed with my R85's yet - but was one of things I was thinking about....

Deffo the R85 spur is a bit weird and is different to "normal" stock gear sets

(I was messing about with a SHS R85 gear set in a v2 box but all gears didn't mesh correctly & seemed like spur was not meshing - could be a higher ratio than a stock 18:1 but whatever - it didn't work properly)

 

However the SR25 & L85 sector's do "appear" similar 19 teeth (not tried the SVD AEG 19 teeth)

so if they did work then the difference would be L85 or R85 has the pre-cocking & SR25 does not

 

The pre cocking on 85's was always a bit hit n miss - maybe ask Sp00n - he has done some work on G&G's & has a R85 spare box I think

soz to drop him in it but I got a hunch that a SR25 sector might be worth trying in L85's to eradicate the semi lock up's perhaps

before people go down the usual 15 tooth piston & spacer route - again I not tried it yet but sounds to me if still using a short stroke R85 sector

then that poxy pre-cocking position might be part of reason still why semi lockups still happen

 

If you have 13 tooth - very short stroke piston btw - most go for convential 15teeth normal aeg piston

and aprox 9mm/10mm spacer behind piston to make up for missing 3 x 3mm teeth)

then you may be able use a "normal" M4 sector with a couple of teeth removed

 

if your sector is a normal M4 one then it should not happen coz it won't pre-cock no more

 

Again - this is my understanding of L85 or R85 problems but like I said I haven't ripped my boxes open just yet

so take all this crap with a pinch of salt - it is just my theory/understanding of it so far

 

best ask Sp00n or others with real hands on experience of G&G L85's....

 

 

SD you need to be very specific with the SR25, some are V2.5 (V2.5 being 19tooth, i believe/have read CA and A&K are) where as G&G SR25 is a (standard) V2

 

yeah i have a spare box (got it off ebay ), atm this spare box is not usable due to the army trigger contacts being pants (sorry to be brutally honest), when funds allow i will be replacing the trigger with a G&G unit (hurry up payday!!!)

 

as others have said, its more then likely, too fast trigger response/expectation, and like you said a faster motor will help

[beastmode]

Thanks for the helps guys. It came with a weird 13 tooth piston as standard as I think they've changed the design on it from the 19 teeth ones. While we're on the subject of pistons I'm looking to swap it for a metal tooth one anyone know if a 14 tooth piston would work as I can't seem to find a 13 tooth piston anywhere. I'll also drop a high speed motor in there and hopefully that will help.

[beastmode]

Anyone have any idea on the piston?

[n1ckh]

You could get a 14 tooth piston and file down the last tooth to make it 13 but you'll need to do AOE aswell, file down the first 2 teeth

[sp00n]

dose it have a piston head spacer?

 

any chance of a pic of the box???

[Sitting Duck]

Thanks for the helps guys. It came with a weird 13 tooth piston as standard as I think they've changed the design on it from the 19 teeth ones. While we're on the subject of pistons I'm looking to swap it for a metal tooth one anyone know if a 14 tooth piston would work as I can't seem to find a 13 tooth piston anywhere. I'll also drop a high speed motor in there and hopefully that will help.

 

Really - they now using 13 or 14 teeth piston as standard ???

 

sounds kinda wrong coz means that piston would have even less stroke 14 x 3mm pitch

than a AK47 or M4's stroke 16 x 3mm

 

odd thing is the L85 or R85 has around a 510 barrel so shorter piston than AK / M4 don't make sense

BUT G&G have done some odd things lately....

 

Normally it used to be extra 3 teeth than aeg 16 teeth

they might call it 15 or 14 teeth (2nd tooth missing already) but add 1 more for pick up tooth

so aeg's use 16 teeth..... - well on sector gear

even if 1 or 2 teeth missing - it still gets pulled back 16 x 3mm + 1/2 tooth to release = 50mm max stroke

L85's etc.... 19 x 3mm + 1/2 nearly 60mm stroke

L85's SR25 - some of them & SVD may use the 19 tooth - 3 x3mm = 9mm extra stroke to allow say 550 to 600+ barrels

(L85 may have some porting near back coz not using full volume quota on 510 barrel)

 

So it does sound a bit weird to now go with shorter pistons than before from the factory

 

here is a couple of posts for you to read perhaps.....

 

http://www.airsoftsociety.com/forums/f10/l85-build-thread-60649/

&

http://www.airsoft-forums.co.uk/index.php/topic/13436-solving-the-r85-piston-problem/

 

a bit old but they deffo used to be 19 teeth by default

have a look and post some pics if possible

[beastmode]

It doesn't have a piston head spacer as far as I'm aware no.

 

I got the gun from brand new so no one else has changed from the stock piston or anything. It is a bit strange for it to have such a short piston agreed.

 

Do you want a pic of the box it came in sp00n? Or a pic of the gearbox?

[sp00n]

interesting regarding the lack of spacer. This is the army gearbox i have (its a G&G clone)

 

[beastmode]

Actually come to think of it is that a piston spacer there?

[beastmode]

My gear box is completely different from yours I have the two piece split gear bo.

[Sitting Duck]

it is a spacer from airsoft world.net

 

http://www.airsoftworld.net/piston-spacer-for-army-armament-r85.html

 

and both boxes split into two - the Army is a clone of G&G's box

 

but gonna back out coz I will admit coz I only know the theory side

I've yet to rip open my R85's, so will let the more experienced - hands on chaps continue

[beastmode]

It's very strange as mine was a brand new gun so why would it have a piston spacer instead of a longer piston.

[sp00n]

yeah that is a piston spacer. looks like your has been upgraded to AEG spec ... this is a good thing

 

mine is 2 piece, the black and metal separate

[beastmode]

That's good at least so does that mean I can put in a regular 14 tooth metal piston and maybe adjust the piston spacer?

[sp00n]

My gear box is completely different from yours I have the two piece split gear bo.

 

like this

 

[sp00n]

That's good at least so does that mean I can put in a regular 14 tooth metal piston and maybe adjust the piston spacer?

 

 

sure dose, though what is up with the current piston? the removed teeth are to correct for AOE

[beastmode]

Ah yes it's exactly the same. I've never taken the bottom Half out my gun that's why.

[beastmode]

Well its plastic teeth and they look like they are wearing away. If I put in a high speed motor I will need a metal tooth piston to handle it.

[sp00n]

look at it this way, if plastic teeth shred ... its a new piston ... metal teeth on the other hand, it may be a new sector too

 

there is 2 schools of thought, some say a metal tooth piston is a must, i look on it as a fail point of something dose go wrong.

 

that said a metal tooth piston will work just fine

[beastmode]

Ok cheers Sp00n I'm going to leave the current one in for the moment, get a new motor and see how it goes. Thanks for your help.