G&P V2 gearbox overspin - HELP

[NickABZ]

Hi there, looking for some advise about my M series V2 gearbox I’m having issues with (possibly overspin).

I’ll try and explain from the beginning.

I bought the gun in February 2015 (G&P Magpul MOE Carbine M4 AEG – two tone as I didn’t have my UKARA), I kept using it at home for taget shooting only, never had an issue. Always used the gun with a 7.4v LiPo (Mini deans) as recommended by the manufacturer. 

Gun specs:

Gearbox: 8mm V2

Motor: M120 High speed motor

A couple of months ago I played my first game and after a while the gun started shooting twice in semi with only 1 trigger pull and sometimes getting stuck which I solved by switching to full, firing and then switching to semi again and everything was fine.

After my second game I decided to open the gun and have a look at the gearbox, the trigger contacts were all black from carbon built up, I replaced that with a new G&P trigger assembly that came with a simple MOSFET (deans plug in this new trigger assmbly so changed my batteries to dean as well), tried the gun again and the problem persisted, after opening it again I’ve noticed the the cut off lever had a little bit of a scrath in one end (nothing major but decided to replace it anyway), replaced it with a new Lonex cut off lever and tried again, problem persisted, opened the gearbox again and noticed the the piston spring had one of the ends flat and the other end looked like it was cut (not flat), replaced that with a new ASG M105 spring and tried it again, problem persisted.

I know I can probably fix this issue with an AB-MOSFET but this is not the solution and a stock gearbox cannot have that much overspin??

Again, just to explain it a bit better:

Using the gearbox only (without the hop attached to it) I pull and hold the trigger once and the gun fires twice (cycles twice), sometimes it doesn’t but the piston can be seen fully back on the window and then the next shot is very quick and sometimes it cycles even more, like if it was in full auto.

I have 2 batteries:

- 7.4v 15c-25c nano-tech airsoft 1200mAh

- 7.4v 15c-25c nano-tech airsoft 2000mAh

One thing that I did notice is that when I use the 2000mAh battery the overspin happens quite frequently and when using the 1200mAh battery it happens on the beginning while fully charged but when the battey gets used a bit the overspin is also reduced quite a bit.

Any help/comments would be appreciated.

I did receive some advice to change the motor to a high torque one, is this going to help or solve the problem?

Thanks.

 

[Iceni]

Is it a stock gear set?

Reason I ask is I run a 18:1 gearset on a 7.4 35/70 2200mAh, And it will double shoot on the initial discharge of the battery. Then after a couple of bursts it'll go back to normal. And that is with a battery capable of 154amps burst on a 35K motor. Yours are only capable of a third of that so to be getting so much overspin with such a low ampage battery you must have something else going on.

It sounds to me like you are running a high speed gearset on a high speed motor. Probably pushing 30+rps.

The solution in most cases is to rein it in to about 25rps. Either with a slower motor, or a slower gearset.
 

 

[NickABZ]

Is it a stock gear set?

Reason I ask is I run a 18:1 gearset on a 7.4 35/70 2200mAh, And it will double shoot on the initial discharge of the battery. Then after a couple of bursts it'll go back to normal. And that is with a battery capable of 154amps burst. Yours are only capable of a third of that so to be getting so much overspin with such a low ampage battery you must have something else going on.

It sounds to me like you are running a high speed gearset on a high speed motor. Probably pushing 30+rps.

The solution in most cases is to rein it in to about 25rps. Either with a slower motor, or a slower gearset.
 

Hi, 

Thanks for the help.

Yes, its all standard, the only upgrades are a new trigger assembly, new cut of lever and new m105 spring.

Gears are all stock. The stock motor is a g&p M120 high speed motor.

There isn't any guarantees that a new high torque motor will solve this, is there? I just dont want to spend money buying a new motor and have the same problem again.

Thank again.

 

[Iceni]

There isn't any guarantees that a new high torque motor will solve this, is there?

There is.

The m120 G&P is a 35.5K motor. You can just buy a slower motor knowing that figure.

Anything below that will slow it down.

ASG have the CNC line up of motors. Very nice units, run cool and the model names are the respected speeds in RPM.

The U-22000 Should put you in to a region without overspin.

https://www.patrolbase.co.uk/asg-infinity-cnc-motor


@Sitting Duck

Get the Ducks conformation on this tho.

Are you sure the cut off lever is performing correctly as well. You mentioned you changed it. Have you checked to see if it's moving 100% freely and knocking the trigger dolly every time.
 

 

[RR01]

Are you sure that the small spring that returns the moving part of the trigger block has been hooked back on, or isn't otherwise broken?

 

[Sitting Duck]

Yeah - I saw this but had a couple of other things I need to do first.....

Stuff isn't quite adding up for a 7.4v modest 15c/25c battery....

I mean that m120 motor is a 15/16 tpa which "should" produce about SHS HT 30k rpm

but as it is ferrite it runs a bit quicker as it turns easier on ferrite magnets than neodym

So @Iceni saying 35k is about right (no load)

Though in practice it is likely running not much faster than 30k as weaker magnets etc...

even so it is unlikely you would hit past 22~23 rps even with bearings & silicone wiring in G&P

Unless you are not running on stock 18:1 gears ???

So this speed/rps is not quite adding up perhaps

The COL was a likely issue to late popping of the trolley allowing excessive overspin double firing

but.....

Yes, its all standard, the only upgrades are a new trigger assembly, new cut of lever and new m105 spring.

THIS could be part of the problem too - some trolleys/trigger switch & tiggers are not always 101% compatible

(well quite often sometimes)

Did you replace the ACTUAL trigger itself ????

See some triggers have a higher/lower sear (tip that pushes the trolley)

Often them cheapo speed triggers are low and slip off the trolley at full pull

Now in your case the trigger if you replaced it might have a higher sear

meaning the COL REALLY has to lift the trolley higher to pop and break circuit on semi

Also not all COL are 101% compatible and anything else you changed could have thrown crap in the mix

This perfection of a trigger/sear JUST being the perfect height to push trolley without slipping

BUT not too high that it pops ASAP is not always a guaranteed certain when replacing stuff

The odd thing is that is WAS working OK originally - usually the speed/rps lowers as gun gets old

(carbon build up in motor brushes etc....)

Now the COL could have worn - how much plinking was you doing in your garden on semi

coz I doubt if it would have work out that quickly

You said the trigger stuck - in the dead zone, doubt if you broke the trolley even if you forced it

(just once or twice usually won't mess up the trolley that badly)

but even then, the area that is popped on semi is underneath and should still pop OK

just the edge/bevel might be a bit chewed up- or that lip at rear of trolley got f*cked from forcing it

I'm thinking that the gun can't really be cycling much more than 20rps - 22rps tops

So think the replacement of 

new trigger assembly, new cut of lever

Has made the situation worse if not better

reckon there is a big sear to lift over and the COL might not be so great in your box

but yeah - reckon a big sear if you replaced the trigger is a likely thing to investigate

rarely does the trigger itself need replacing and if it does close attention should be paid

to how all the combined parts work together - a fine balance of just the right height

enough so it doesn't slip off the trolley

but not too much that the COL needs to lift 6ft to pop the trolley off the sear

(yeah exaggerated I know but you get the idea)

bit of an odd one and sure I've missed or not spotted some stuff

but think certain new parts have increased the issue or not helped like you hoped

or I've totally misread something

 

[NickABZ]

There is.

The m120 G&P is a 35.5K motor. You can just buy a slower motor knowing that figure.

Anything below that will slow it down.

ASG have the CNC line up of motors. Very nice units, run cool and the model names are the respected speeds in RPM.

The U-22000 Should put you in to a region without overspin.

https://www.patrolbase.co.uk/asg-infinity-cnc-motor


@Sitting Duck

Get the Ducks conformation on this tho.

Are you sure the cut off lever is performing correctly as well. You mentioned you changed it. Have you checked to see if it's moving 100% freely and knocking the trigger dolly every time.
 

Hi, thanks again for your time, much appreciated.

Thanks for the motor option, will this 22k motor have much of an impact on the performance?

Yes, I've only replaced it because the original had a hair sized scrape in one end and I tought that would be the culprit.

The new cut of lever moves very freely without the spring and moves well when the spring is attached too.

By trigger dolly you mean the plastic trigger assembly part that moves and is spring loaded? If yes, I assume it does as when the 1200mAh battery is at half power I have zero issues.

 

[Sitting Duck]

The ASG motor will cost you about £60 with postage

yes it is a very good motor but afaik an O type pinion gear

A cheaper option is the zci 22tpa £30 and if msg pete on here or fb

he might do you a deal of nigh on cheapy postage - plus is a D pinion

https://www.ak2m4.co.uk/internal-parts/motors-parts/zci-motor-high-torque-long

still might need to investigate the high trigger sear, might be wise to refit old trigger

There is not enough bandwidth on this site for me to write a tutorial on trigger mods

there are loads out there about a hairline - well reduced trigger pull mod

But they are a real PITA and time consuming to do

The flip side is that you gain an ENORMOUS understanding to how it all works

The perfect trigger sear as I said it one that is JUST the right height

but then there is other stuff like limiting the trigger pull a little

so that it doesn't continue to jam against the trolley at full pull so much that they are fighting to pop

(the tigger is ramming the trolley with a ogre forcing the trigger so trolley is struggling to lift off sear)

the sear edge should be slightly rounded and smooth - but NOT completely rounded but not ultra sharp either

a light smear of grease to ensure it slips off sear in operation

DO NOT F*CK WITH YOUR TRIGGER !!!

I only mention this as some guides mention gluing more metal to trigger to mod

but fail to explain the tip of sear in AEG's should be slightly slightly rounded or smoothed

to ensure it operates/lifts and finally pops effectively off the trolley

most triggers will be smoothed already at tip

you mess up modding a trigger or filing the sear - you are f*cked

imho people should avoid even looking at trigger mod if trigger works OK

if the trolley is jumping off a short trigger sear - then maybe have a go at mod

is what I say to people - if you screw up you are f*cked so avoid an expensive lesson if possible

if it's f*cked - jumping off trolley, trolley in good condition but low sear

then yeah you got little to lose is what I say about trigger mods

but still a f*cking PITA gluing, waiting for it dry, filing bit by bit, tiny increments

checking - oh ffs the checking of how crap works, jeeez

more filing, more soothing, more checking - ffs MORE CHECKING

it is a real PITA but you do learn a lot I'll admit but still.....

testing - rotating the sector on semi, keep rotating the sector just at piston release point

if the trigger sear is not fighting against trolley at full pull

and the sear is not too high...

you should get a really light click as the trolley pops off the sear

needing very very little force to rotate the sector to pop the trolley

I actually like the boxes with a trigger tang limit that is easier to mod the trigger pull limit

so the trigger is not ramming the trolley at full pull

in essence what works best is the trigger stops at say 95% full pull so trolley has a whisker

of wiggle room to shift slightly as it lifts and pops off the sear

(hard to put into words but that is some of the crap that ensures a very light popping off the sear)

It is difficult to put into actual words what crap to check for but there is more to this trigger/trolley bollox

than you first simply assume it will all just work - ergh at times it doesn't

No you should not f*ck about too much with trigger/trolley - this isn't the time to learn by many mistakes

but just saying try the old trigger if that works better and hopefully not so high but won't slip off trolley

I mean if you had a box of bits like most of us have....

you would/could normally try a mixture of bits like triggers

(plus piston heads/cylinders etc... looking for the perfect combo of parts that operate 101% perfectly together)

way way too much info as per usual - don't f*ck with stuff but try the old trigger is what I mean

maybe the cheapo zci could work to lower the speed a bit

DON'T rush into anything though, step back review options and what you did/didn't do

often changing stuff means reverting back to previous stuff (like old trigger maybe)

but at same time don't steam in messing with stuff more that will no doubt make $hit worse

if you ever change stuff - always make close comparisons with old/new parts

TM compatible is a friggin' myth in airsoft

it should be labelled as TM compatible - ISH !!!!

 

[NickABZ]

Are you sure that the small spring that returns the moving part of the trigger block has been hooked back on, or isn't otherwise broken?

Hi,

Yes, the spring works fine.

 

[Iceni]

Thanks for the motor option, will this 22k motor have much of an impact on the performance?

Yes. It'll slow the gearbox down considerably, and may put a lot of demands on those batteries.

1) Speed is proportional to voltage
2) Torque is proportional to current
3) Power is the product of speed times torque.

You drop a high torque motor into a gun and you expect the amp draw to increase. The voltage is going to remain constant, but the power factor for the gun will go up. That increase in power factor means the batteries that were previously only supplying 10 amps now have to deal with 15 amp draw, Draining them faster and pushing them closer to the amp limit of the cells.

That little 15c 1200mAh battery can only supply 18 amps continuous. And I reckon with a high torque motor pushing 150watts at 7.4v (8.4 fully charged) you are right on the danger point for that battery (17.8amps of 18 amps).

But you need to be sure it is the motor. The Duck has given you a far better set of answers than I could. And I would personally take his advice and go through the whole trigger setup with a tooth comb looking for the problem.

The initial post you made about a 7.4 15c 2000mAh battery giving overspin was the reason I flagged him in the first place. The numbers don't add up.
 

 

[NickABZ]

Unless you are not running on stock 18:1 gears ???

I'm not sure what set of gears I'm using but they are stock.

Did you replace the ACTUAL trigger itself ????

I've replaced the trigger assembly, more precisely this one: http://airsoftzone.co.uk/mosfets/m4-mosfet-teflon-switch-assembly-rear-wired-gp

I haven't touched the trigger. Original trigger assembly attached.

Now the COL could have worn - how much plinking was you doing in your garden on semi

coz I doubt if it would have work out that quickly

Not a lot, the original COL had a really really small scratch. Photo attached.

but even then, the area that is popped on semi is underneath and should still pop OK

just the edge/bevel might be a bit chewed up- or that lip at rear of trolley got f*cked from forcing it

I just had a look at the old trigger assembly and the plastic bits are all fine, nothing chewed up or anything like that, just a little bit where the COL catches the trolley but I think it wasn't that bad. I'm starting to think the carbon build up is what caused the initial overspin and when the trigger assembly was replaced it is not working properly.

bit of an odd one and sure I've missed or not spotted some stuff

but think certain new parts have increased the issue or not helped like you hoped

or I've totally misread something

It is a bit of an odd one, thanks again for taking the time to think about it and to write all of this.

I'll open the gearbox again and will inspect the new trigger assembly workings to make sure everything is fine.

View attachment 37521

View attachment 37522

View attachment 37523

View attachment 37524

View attachment 37525

View attachment 37526

Yes. It'll slow the gearbox down considerably, and may put a lot of demands on those batteries.

1) Speed is proportional to voltage
2) Torque is proportional to current
3) Power is the product of speed times torque.

You drop a high torque motor into a gun and you expect the amp draw to increase. The voltage is going to remain constant, but the power factor for the gun will go up. That increase in power factor means the batteries that were previously only supplying 10 amps now have to deal with 15 amp draw, Draining them faster and pushing them closer to the amp limit of the cells.

That little 15c 1200mAh battery can only supply 18 amps continuous. And I reckon with a high torque motor pushing 150watts at 7.4v (8.4 fully charged) you are right on the danger point for that battery (17.8amps of 18 amps).

But you need to be sure it is the motor. The Duck has given you a far better set of answers than I could. And I would personally take his advice and go through the whole trigger setup with a tooth comb looking for the problem.

The initial post you made about a 7.4 15c 2000mAh battery giving overspin was the reason I flagged him in the first place. The numbers don't add up.
 

Hi,

thanks for all the info, it makes sense!

You are right, I'll look into the trigger assembly again and will check how everything is working.

Again, really appreciate the help you guys are providing! it has helped me a lot as everyone else just says to put an AB-MOSFET into it but it doesn't make any sense.

Will keep you guys updated.

Also, the spring photo I've attached in my earlier post is the spring I've mentioned in the beginning (Stock spring) now replaced by an ASG M105.

Cheers.

 

[NickABZ]

yes it is a very good motor but afaik an O type pinion gear

A cheaper option is the zci 22tpa £30 and if msg pete on here or fb

he might do you a deal of nigh on cheapy postage - plus is a D pinion

What is the difference between an O type and a D type, I don't recall checking this in my stock motor, I didn't see anything different so maybe its an O type?

still might need to investigate the high trigger sear, might be wise to refit old trigger

Thanks for the other motor option, I'll have a look at it as well. but you're right, I'll check the parts I've replaced and will make sure everything is working as it should.

DO NOT F*CK WITH YOUR TRIGGER !!!

I only mention this as some guides mention gluing more metal to trigger to mod

but fail to explain the tip of sear in AEG's should be slightly slightly rounded or smoothed

to ensure it operates/lifts and finally pops effectively off the trolley

most triggers will be smoothed already at tip

HAHA  I get why you thought I was talking about the trigger, maybe I should've explained that a bit better.

Thanks for the trigger tips though, I can see you've done it before?

but at same time don't steam in messing with stuff more that will no doubt make $hit worse

if you ever change stuff - always make close comparisons with old/new parts

Thanks! I'll hold before buying anything else, as I said before, I'll open it up again and check the functioning and will let you guys know how it goes.

I know I've said it before but I really really appreciate the time and knowledge you guys are sharing.

Thanks!

 

[Iceni]

What is the difference between an O type and a D type

If you look head on the pinion gear on the motor.

A type O is a round rod. It's a pressure and metal glue fixing, using loctite red thread lock.

A type D is a round rod with a flat section cut into it (looks like a D) and the pinion has a grub screw in the side to locate and lock it.

 

[Sitting Duck]

View attachment 37526

That is a chopped spring for sure - or it broke

What if the fps may I ask ???

just in case you got a m85/90 sub 300fps gun - that will overspin more

The odd thing it was OK but got worse

now if the spring BADLY faded or worn so fps dropped from gun being stored precocked

then yeah it will overspin more

Another thing popped into my head is if the trigger contacts are too tight

them contacts if too tight - (and some tutorials still suggest closing them ffs)

it can grab onto the trolley and delay the trolley flying back & breaking the circuit

I had a new FireHawk do that to me once and stuck on full auto

I'm hitting the gun at the side, flicking the trigger but she' going full auto without my finger on trigger

then never seemed to do it again - WTF ?????

didn't open it, so don't blame me, but didn't need a tech I needed a priest to cast out the demon possessing it

Yeah - them contacts "could" also be a bit tight - that might might increase a possible delay in popping

I mean sear could be a smidge high but if you haven't changed trigger then we can likely rule that out

(and avoid the urge to start any modding ffs)

The cut spring - jeez that end is f*cking horrid might be pushing out low fps which may increase overspin

The motor will help - in fact the amps "should" lower on a 22tpa than say a 16tpa

the speed will drop a bit but also the amps with a 22 tpa

on faster motors they simply drain the battery quicker

slower motors the battery lasts longer because the running amp draw is less so drain battery less

you "could" be looking at running amps:

12/13 tpa 20 amp plus FUCTIFINO

16 tpa 15~20 amp

22 tpa 10~15 amp

28 tpa 7~11 amp

The above is a MASSIVE ultra rough ball park estimate of builds

varying greatly due to gearing, springs etc.......

but like for like comparisons - ROUGHLY

wondering if spring is quite light and contacts quite tight

these will add to late release and overspin

mega kudos for pics though

that carbon build up means that motor was drawing some amps

I think that might even be a 40k motor, they are quite quick and can run warm them m120's

What is the difference between an O type and a D type, I don't recall checking this in my stock motor, I didn't see anything different so maybe its an O type?

The D type is easier to change if it gets chewed up down the line

if tiny grub screw fails to undo, normally heat up the old worn pinion by lighter

(or gas hob/burner CAREFULLY)

undo, remove & replace with new pinion

The O type is what die hard techs claim rotates in more precise unison

but mostly - nahhhhhhhhh unless it is so loose and wobbles like f*ck off center

But to remove is a bit more involved with a bit more heat maybe

the issue comes when trying to refit a new O pinion

yeah you can cool motor in fridge/freezer

warm pinion and it should fit on the O shaft ok

people have tried to hammer it on and bent the spindle/armature

really you need a motor/pinion puller for O pinion replacements

yeah you can scrape by - but in general you need puller for O pinion motors...

View attachment 37527

I mean you probably won't need to replace the pinion for quite a while if all working sweet

but just pointing this out 

I " think " a G&P m120 might have an O pinion

but the cheapo clone Big Dragon Motors have D type pinion

see the tiny grub screw on pinion ??

 

[NickABZ]

That is a chopped spring for sure - or it broke

Yes, I just don't know if it broke while I was using it or if it came like that, no bits of spring came out the first time I opened it.

What if the fps may I ask ???

just in case you got a m85/90 sub 300fps gun - that will overspin more

The first time on the field the Chrono said it was shooting average 340 FPS on .20g.

Maybe the spring was cut at factory? Specs says it should shoot 350FPS.

Another thing popped into my head is if the trigger contacts are too tight

them contacts if too tight - (and some tutorials still suggest closing them ffs)

it can grab onto the trolley and delay the trolley flying back & breaking the circuit

They may be, I'll check that once I open it again, when the trigger assembly was replaced the gun only shot when the trigger was pulled 100%, if I pull it 98% it wont fire, so I changed it a little bit to fire at about 90~95% trigger pull, does that have to do with it being tight? Can I have a not so tight trigger assembly and still fire at 90% trigger pull?

I had a new FireHawk do that to me once and stuck on full auto

I'm hitting the gun at the side, flicking the trigger but she' going full auto without my finger on trigger

then never seemed to do it again - WTF ?????

didn't open it, so don't blame me, but didn't need a tech I needed a priest to cast out the demon possessing it

That did happen to me once in full auto before I changed the spring and adjusted the 90% trigger pull, but it stopped after a second or two.

Can only imagine seeing it on full all the time and not being able to stop  

The above is a MASSIVE ultra rough ball park estimate of builds

varying greatly due to gearing, springs etc.......

but like for like comparisons - ROUGHLY

Thanks anyway, anything helps!

mega kudos for pics though

that carbon build up means that motor was drawing some amps

I think that might even be a 40k motor, they are quite quick and can run warm them m120's

It does get really really hot sometimes, especially during testing to see if the overspin has been fixed.

Hopefully, with the new MOSFET the carbon will not happen again.

 

[Sitting Duck]

I'm amazed why the mosfet needs FOUR MOSFETS ????

I mean it isn't an AB mosfet coz positive doesn't go to it so can't brake

there is no TVS diodes just 4 mosfets sharing the load but no spike protection

This has f*ck all to do with overspin but just saying

well if these are connected series/parallel there might a tiny whisker of one staying on a bit later

but usually one mosfet or two would more than enough in parallel sharing for a normal mosfet

I originally thought - oh it must be a parallel twin AB mosfet

two negative & two positive mosfets -but no positive wire runs to pcb

so is a regular non AB mosfet with FOUR friggin mosfets ????

probably little to do with issue but just saying....

 

[Sitting Duck]

Yes, I just don't know if it broke while I was using it or if it came like that, no bits of spring came out the first time I opened it.

The first time on the field the Chrono said it was shooting average 340 FPS on .20g.

Maybe the spring was cut at factory? Specs says it should shoot 350FPS.

They may be, I'll check that once I open it again, when the trigger assembly was replaced the gun only shot when the trigger was pulled 100%, if I pull it 98% it wont fire, so I changed it a little bit to fire at about 90~95% trigger pull, does that have to do with it being tight? Can I have a not so tight trigger assembly and still fire at 90% trigger pull?

I personally think cutting springs is a bit of a bodge imho

you can do it but should crimp/finish off the end coils so it lays smooth/lat like other end

If a retailer or G&P does this to their export models I'm a bit unimpressed tbh

ffs - just fit a proper spring or finish the thing properly is my feeling but hey ho

The tight contacts - they should make contact, you should just see the contacts move

as trolley enters

but they should not GRAB the trolley tightly that it could delay or hold onto it

People think: Oh that trolley spring will pull it back no problem....

Yeah ???

Could say the same about a bb jamming in bucking, that tappet spring should ram the bb into hop

but it don't always guarantee to feed a bb if the bucking lips are just a smidge too tight

I'm NOT saying the contacts are too tight - I'm say CHECK they aren't too tight

I haven't got the thing in front of me, I'd be doing this and that

watching this n that, probably think right that can go, don't like that either

All I can do is offer stuff to look for but even then I'm probably throwing more & more into the mix

most likely you need to drop down to a zci 22 tpa to be able to use the gun a bit better

but still seems to running a bit quick/overspinning all the same

can't see how on 7.4v you can be hitting much past 20rps so gun should not be overspinning

unless certain bits ain't functioning correctly

what those bits are - well that is still some guesses or stabs in the dark as we don't have it in front of us

 

[NickABZ]

Hi again - UPDATE - 

Opened the gearbox and checked all the parts again, COL is working fine and moving freely, the trigger contacts were also fine but I readjusted them so they are not tight and are just about right to get a contact and get released quickly.

After doing that I also shortened the trigger trolley spring by 2 rings, hoping that should pull it a little bit quicker than usual.

While testing the trigger trolley it worked fine, had the trigger fully pulled and the COL engaged, rotated the gear and it popped the trigger trolley with ease, multiple times.

Connected the grip and motor to the gearbox only and inspected the spring/piston window.

While using the 7.4v 15c-25c 1200mAh (nearly discharged) battery everything was perfect and there were very little overspin (not double shooting), the piston was cycling and stopping with approx. 15mm distance from the window (average) (which I think is great? Normal?).

While using the 7.4v 15c-25c 2000mAh (fully charged) battery everything was also perfect and the overspin wasn’t that bad (not double shooting), the piston was cycling and stopping with approx. 5mm distance from the window (average, sometimes closer but never showing on the window) (also normal?).

During testing the motor got really hot (not to a point where I couldn’t hold it but it was noticeable hot) and I left it to cool down before taking the motor off again and reassemble the gun.

Once it cooled down I took it off and assembled the entire gun again, tested with the 7.4v 15c-25c 2000mAh (still nearly full charge) and the first trigger pull on semi fired 2 shots… sometimes firing 3 and once it even went full auto on semi.

Really frustrating experience…

My theory is that the motor had some sort of issues and is firing too quickly? Not just now but since the issues appeared (don’t know).

Do you think the motor you’ve recommend will work fine with my current batteries?

Thanks,