V2 Gearbox not working

[Callum Hornsby]

Hello everyone looking for some insight into why my G&G cm gearbox isn't functioning. I opened it up in order to change a faulty cylinder head, replaced the cylinder head and reassembled the gearbox. I then had things come up and it was forgotten about (for nearly two years). So about two weeks ago I cracked it back out and decided to fully assemble it and get it game ready, I got my battery fresh off the charger and plugged it in and to my surprise nothing happened.... I instantly thought it would be the battery so got my voltmeter out and the battery read 8.4 volts (rated voltage of my nimh battery). So then i thought maybe the motor was faulty so took that out of the pistol grip and it functioned fine. My next thought was the gearbox was incorrectly assembled so i checked but could not find fault everything seemed fine. So at this current time I'm totally at a loss any help is much appreciated.

PS (I know the trigger spring is missing I have one on the way)

 

[Sitting Duck]

motor height or shimming....

what shims are on bevel & sector gear ???

I assume they are in other half of gearbox casing

It is stalling for some reason - possible shim/motor height

plop bevel in other half of box and ROUGHLY CHECK HEIGHT....

SORT OF ROUGH ULTRA ROUGH GUIDE BUT WORTH A BUTCHER's

motor pinion right on the edge - full meshing but not too far in nor too far out....

 

[Sitting Duck]

HOLD UP MEGA DAFT QUESTION

YOU GOT MOTOR POLARITY CORRECT ???

COZ WRONG POLARITY IT WILL TRY TO RUN IN REVERSE

BUT STOPPED BY ANTI REVERSAL LATCH - soz for shouting

 

[Callum Hornsby]

Hi motor height seems okay to me, possibly could be shimming but I have kept the shimming identical to the stock g&g shimming and have never changed it. As far as motor polarity goes I'm sure I got that right positive is to the left as you hold the gear box with the air nozzle also facing left.

 

[Samurai]

Is that rust on the bushings?

Put some grease in it where it's needed. It looks bone dry on the first pic and on this last.

Is there a click from the motor when you pull the trigger?

Charge the battery full too, maybe it drops voltage under load.

 

[Sitting Duck]

I instantly thought it would be the battery so got my voltmeter out and the battery read 8.4 volts (rated voltage of my nimh battery).

actually all batteries fresh off charge have about 1v more

Some 8.4v's are quite lame by today's standards

you 8.4v fresh off charge should be over 9v

So try a charge up like Samurai said

wiring - yup red positive usually up front right close/behind trigger

now, some G&G's, the red/posi wire runs downwards to terminal as usual

some of the G&G's the red wire comes in on the right, but makes a sharp left then both red+black run down back of motor....

not a big deal but G&G do chop n change stuff

sometimes the two wires run down same side/back of motor

other times two wires run down the to motor on either side

friggin' odd thing, like mostly bronze bushings but some CM16 are bearings

or mostly phillips but then you get hex screws in next gun/gearbox

just say so you route wire correctly, watch the motor connectors don't break

slap a smidge of grease on gears inc pinion - just a bit to avoid it being bone dry

you could have a chip/burr/bit of plastic jammed in gears, test they turn ok

can't see anything really wrong atm, he says burning the tea, rushing back kitchen fire

 

[Hangtight]

Do you have the selector plate installed correctly? Looks like those trigger contacts are the type that need a selector with a metal plate to complete the circuit.

Check the motor polarity just in case.

 

[Sitting Duck]

Do you have the selector plate installed correctly? Looks like those trigger contacts are the type that need a selector with a metal plate to complete the circuit.

Check the motor polarity just in case.

G&G's don't need them prongs at back bridged like SRC Cyma M4's etc.....

(there are no prongs)

They got prongless switches, well on all the ones I opened with metal safety arm etc....

(Modern SHS v2 switches are prongless but old there were some prongy ones about (clones/old stock)) 

(I moan about some G&G's but some things they actually did well on here n there)

 

[Callum Hornsby]

Is that rust on the bushings?

Put some grease in it where it's needed. It looks bone dry on the first pic and on this last.

Is there a click from the motor when you pull the trigger?

Charge the battery full too, maybe it drops voltage under load.

Not rust just camera angles looking funny.

There is a click when I try to fire but nothing else.

Battery is fully charged using smart charger (however battery is nearly 4 years old)

As far as sector plates goes I've never uninstalled it or played with it so should be no issue,

I'm now also sure motor polarity is correct.

All being said i went to put some grease on the gears and noticed a small chip on the bevel gear could this be the issue?

 

 

[Sitting Duck]

All being said i went to put some grease on the gears and noticed a small chip on the bevel gear could this be the issue?

 

well it won't help for sure, now where did the chipped bit go ???

that bit may have got caught up, causing lock up

luckily the chip is on inner, not so deep chipped tooth

there is more depth on outer ring teeth so "should" work for a while - but don't sue me

roll motor on bevel to see smooth it rolls meshes with old gummy bit of bevel (toothless bit)

IF it seems to roll ok it could be worth trying it and get new bevel or stuff on order

It ain't like fine wine, not going to improve with age

need to careful more crap don't chip off

but a new set ofgears/bevel means checking shimming etc...

so it is your call I'm afraid - even just for a quick game day

What caused it to chip, did it lock before - looks in good nick elsewhere

(f**king bone dry like Samurai said - did you clean it with washing up liquid or something??)

poor G&G stock gears I expect but that bevel with mild use is a bit of a shock

 

[Callum Hornsby]

Was bone dry never cleaned it off tho so god knows where it all went got some on there now tho. As far as the chip is concerned i don't know how it happened and the chip is not present anywhere in the gearbox.

The pinion gear runs fine over the chipped tooth so does not seem a problem tho I shall be sure to get it replaced asap. I made a bodge job of the wiring (deans to mini tamiya) up to my mates gun I had laying around and i had the same issue I'm starting to think this can all be pinned on a old battery and not the gearbox at all.

 

[Sitting Duck]

Was bone dry never cleaned it off tho so god knows where it all went got some on there now tho. As far as the chip is concerned i don't know how it happened and the chip is not present anywhere in the gearbox.

The pinion gear runs fine over the chipped tooth so does not seem a problem tho I shall be sure to get it replaced asap. I made a bodge job of the wiring (deans to mini tamiya) up to my mates gun I had laying around and i had the same issue I'm starting to think this can all be pinned on a old battery and not the gearbox at all.

All done stupid stuff tearing into things

I had a misfeed problem, tore box apart twice before I realised the mid-cap I was testing now n then 2 bb's jammed

right at the U bend they would get wedged - but mid-caps feed best

BB's kept falling out when pulling mag, bb's still showing etc....

Must be fine - right ???

WRONG, BB's have fed but no more tension to push up loads more so stop feeding

One in hop feed tube, fall out, bb still showing in mag etc...

pull spring latch - no expected stream of bb's flying in your face coz the rest are all jammed at U bend below

Now the STUPID thing we always say try other mag/battery etc....

So I should have known - nope

Delay clips, sanding crap, cutting coils on tappet spring - yup did all that crap

It must be something like that - RIGHT ?????

wrong again, eventually I popped in a high cap, flawless feeding

AAAAARRRRRRRRRRRGGGGGGGGHHHHHHH air was dark navy blue

How that friggin gun didn't follow the mid-cap down the garden I'll never know

I'm the biggest idiot on here coz I should have stopped to think practicing what we preach etc....

try another mag/battery first - just in case

Well fingers cross you get it up & running easily, not making the mistake after mistake this fool has done

Best of luck - PS +1 or heck +2 for pics, really helps us to shed light on stuff etc....

(others please note: we only have one Jedi Master on here, the rest of us can't read minds that easily)

Soz if I told this story loads of times, but not too proud to admit my own screwups....

 

[Callum Hornsby]

Thank you all so much with your help, Im heading to Edinburgh next week for a bit of a holiday so ima pop into land warrior airsoft and pick myself up some goodies including a new battery, gear set and shims. So if all goes well you shouldn't hear from me in this section of the forum for a while.Thanks again for all the help .

 

[Chris_B]

I was going to suggest to measure the battery voltage whilst pulling the trigger. Typically the voltage should dip a few volts but nothing more. If the battery voltage dips to say 2 or 3 volts, the battery has lost it's capacity.

A chaffed wire can also have same symptoms.

As a FYI, nearly all AEG motors I have seen have a '+' symbol stamped next to the terminal on the back.

Definitely replace that bevel gear as more could chip off and render your G.Box fubar!

 

[Callum Hornsby]

Quick question guys got my new battery, gears and motor and she runs like a dream   however I also replaced my nozzle (old one cracked) with a nuprol m4 nozzle with double o rings and here is where my new problem occurs, I have a ZCI cylinder head and the nozzle is a tight fit due to the o rings. When cycling there is no problem with retraction of the nozzle but when it comes forward again it does so very slowly meaning I’m gonna have consistency and feeding issues big time when I get home from holiday. Have any of you experienced this do I just take the o rings out? or one out? Or will it wear in eventually? 

Cheers for the all the help again guys

Callum

 

[Sitting Duck]

possibly take one out if you can hook one of them out OK

nozzles will NEVER be a 101% seal - just won't happen

Nuprol - more like Rocket/RA - SHS rebrand

SHS do two red M4 nozzles

the double o-ring version has a slight tiny cross at the end

(to prevent bb suck but in reality never really needed)

double o-ring is not needed - well unless your cylinder head spout is quite small

nozzle should move fairly easily forward n back - think of this 20 times a second or 20rps

It will never seal perfectly, some still use stock non o-ring nozzle if the fit is decent

the way air flows, you lose little unless it is two sizes too big

If you wish to go nutz, get compression really good with piston head

really strong piston head sealing, then pop the front of cylinder in a sink/bowl of water

(like checking for a puncture with tyre/inner tube)

You might see bubbles forming at cylinder head indicating a leak there 

the nozzle will leak a bit when sitting forward in operation, never a 100% air tight seal

gotta flap back n forth, so at best it should only be a modest snug fit

grease the spout of course,

you can cut a coil on tappet spring and bend the end to a loop

effectively increasing the spring strength to return quicker - but only for fast/rapid stuff or DSG's

(shouldn't compensate for tight fitting nozzle)

Also some cylinder spouts do vary a smidge, some nozzles are damn tight on certain heads but OK on others

By the sounds of it, you need to consider removing at least one o-ring

(most people just go with single o-ring nozzles, next time just buy the single version without the X)

 

[Callum Hornsby]

Thanks for the quick reply as always I shall try tonight with removing one if that still don’t work I’ll take out both the stock g&g one had no o rings so I’m not really losing out on much.