V2 gearbox problems

[Lt Earholes]

I brought a new spring for my g&g combat machine m4.

Took it all apart and changed the spring.

Once it was all together I checked the air nozzle/tappet plate, it does move back and spring forward, after I connect the battery and try trigger I get the sound of gears moving then it sounds like it jams, the air nozzle/tappet plate is now stuck in the back position and won't spring forward.

 

This is my first RIF so have no clue what I'm doing, followed a video, tried assembling it together about 3-4 times and I get exactly the same results.

 

Can anyone with experience tell me where I'm going wrong?

[sp00n]

what size spring? is the battery charged?

 

is the spring guide in right?

[Sitting Duck]

piston jumped out of its runners when closing box

ar latch not back in place - use a small earth/neodym magnet to hold that git in position

shim(s) dropped off and now gears not shimmed correctly

 

motor height - you have got pistol grip fitted correctly

polarity of motor - G&G's have the wires going up one side in pistol grip

so you got them on the correct way ???

 

soz if it sounds a little daft but in effect it should of been straight forward

but more often than not ya first few attempts opening a box up doesn't always go to plan

(mine didn't - jeez and I'm still learning but G&G's are nice boxes to work on)

 

also don't over overtighten screws up too much, that will knock the shimming out a bit.

You mega tighten them and it will result in much tighter shimming

(ya supposed to keep checking shims on a closed up box - but you knew that)

 

Hopefully you didn't mess with shims/gears so they should be ok as long as you didn't go mega nutz when tightening screws

them fine threads can strip if you keep going too heavy handed - reckon tighten as much as possible using thumb + index finger

unless you are really weak a good turn with just thumb+index will result in tight but not too tight as actress said to bishop

 

hard to say for deffo but either gears not meshing correctly or piston not in the rail grooves as you closed up box

[Lt Earholes]

M95.

Yes, tried the gun before I dismantled it and was firing fine.

From as far as I can tell it is, the spring guide has the locating pieces on it and I put them where the corresponding locating positions were on the gearbox housing.

[sp00n]

have you tried reassembling it with the original spring?

[Lt Earholes]

I'll have to take it apart again tonight as I have gone out now cause it was annoying me. (Get some fresh air, before I smash it into a million pieces)

I know the ar latch is right, as first time I took it apart it wasn't so then realised where it was supposed to go.

[Sitting Duck]

OK - try to ensure the cylinder port or hole is running in line with piston grooves

that way you can check when you close up she is still looking like all in position.

 

yup you need 3 hands to close it up but then the 3rd hand gets in the way at same time

fish and prod gears etc.. to pop through their holes correctly whilst trying to keep the lid on

yeah "fun" is one word - bollox is another, plus loads of others too

 

looks really easy but they have been doing it for yonks and they are used to it - they make it "look" easy

 

if you feel confident and have time - remove spring and cylinder/tappet

then check all gears are moving nicely and not crossing on a closed up box

ya finger can spin sector gear/piston gear thingy through the cylinder cut-out

I really don't think they will be out of alignment but might just be worth checking that them gears spin lovely

 

Reckon it may be piston not situated correctly - so give it a once over, piston head look ok

see that piston glides along rails all nicely too whilst you are about it.

Stock G&G CM16 piston's don't have bearings on piston head so doubt if it came undone

 

compare springs old + new and like spoon says if all else fails put old one back

 

it is something really daft but very hard for anyone to accurately pinpoint it like this

hence just a few things to check - take your time you will suss it I'm sure

[Lt Earholes]

Do you know where I can just buy a fully built gearbox, tokyo marui preferably as most of there guns I've seen shoot low 300's so can just drop it in.

[Sitting Duck]

you can buy a QD - quick spring change box also

the back of spring guide pops out without having to dismantle the whole box to change spring

 

check

 

ak2m4.co.uk - but he might be out but deffo ask him first

helmetworld.co.uk on ebay or direct site

patrolbase might do them too - all UK mofo's btw

 

so you could pop in a qd box and get back in game, then sort out ya old box or drop it into somebody

[Lt Earholes]

Is this any good?

http://www.ak2m4.co.uk/internal-parts/gearboxes-complete/zci-qd-gearbox-front-wired

[Sitting Duck]

cool - they are back in stock

 

if ya G&G is front wired - bit of a $hit if its rear wired

 

that is the stuff - think it is like a 6mm allen key or torx in the back, twist 90 degrees

and spring guide + spring come out - bob's ya uncle

 

park it properly in semi first, only recommended for say up to m120 or m130 springs max

often they have micro switch system on trigger than classic plunger switch type

if it has micro switch do not run 11.1v lipo's on there as smaller tiny contacts will burn out on higher juice

(a mosfet is recommended for any box using micro-switches - well fet is recommended upgrade for most tbh)

 

yup that is the kiddie - worth considering as a backup option in my book to get ya going again

he's on here - pm him and he might be able to do a deal & offer help on getting old box working again

 

most of them come with a m110 or m120 spring so a little hot to use but hey ya got stock & m95 spring

[Lt Earholes]

Well I play cqb and it's single shot only, so there is no need for lipos so guess this would be perfect for me, if I decide to play outdoor I'll just buy a new gun.

[Sitting Duck]

most of us have more than one gun - ahem yeah I gotta a spare you could say

but by then you probably have sussed it all out a bit more....

 

then got old G&G box sorted and you will have a spare box for either cqb or woodland aeg

no worries, no major drama to get ya going again

[Lt Earholes]

Cheers for the help

[straffham]

I've used a couple of ZCI v2 shells in projects (also from ak2m4) and they are good for the money, really simple and come with all the electrical/fire selector/trigger parts already installed, just fitting gears and piston/cylinder components as required. The quick change spring is a useful feature but bare in mind in most guns you will still need to remove the gb to change the spring (unless it has a stock tube which screws into the receiver real steel stylee like Ares) Also the front opening will almost certainly need opening out slightly with needle files so the hop unit seats correctly, which means if you buy the complete gb it will need disassembling to avoid getting bits of metal in the working parts).

However tbh I'd keep trying to sort the problem out first before splashing out on new parts/gbs.

[RR01]

Just a thought but did you put the spring in the right way? Some are multi-directional but others have closer coils at the back end that need to sit on the spring guide. If the gearbox is cycling enough to pull the spring back but then gets stuck before it can turn over to release it then the spring "might" be jambing on the inside of the piston at full cock if it's in the wrong way.

[Lt Earholes]

The video I watched while doing it mentioned the spring so I made sure it was the right way.

Decided as JD Airsoft is my closet store, I'm going to ring them tomorrow morning and see if they will have a look and if they will drop it off.

[Sitting Duck]

UHmmmmmm

 

not being funny but a couple of members have had some - shall we say

not quite so brilliant levels of service from JD's tech guys....

 

http://www.airsoft-forums.co.uk/index.php/statuses/user/7335-bottledtorment/?status_id=6012

 

might just be a rare thing or the young trainee did those guns

but just letting ya know

[Lt Earholes]

Well I decided last night to charge my battery so it was defiantly full.

Then did what sp00n said and put the old spring back in, now it works perfectly fine, have no idea why.

I did exactly the same as before but with the original spring.

This m95 spring is supposed to reduce my fps so surly it would take less force to pull back?

 

My fps is the same as it was before, floating around the 345 mark.

[Sitting Duck]

weird ???

but kudos to Spoon & RR01

 

presume that perhaps a M95 might have been an Element one ??

have used the M105's in a few builds and been fine

 

anyway if 345 is a big problem for your site, then maybe look at doing Angle Of Engagement

a small sorbo or rubber pad washer placed on cylinder head that moves the position of piston back

so the initial bigger tooth or pickup tooth engages better & smoother

the piston is drawn in a smoother straighter pick up path so to speak

 

G&G black piston has a tooth missing - 2nd tooth already

 

place one or two max on cylinder head, sometimes shave a little on the next 3rd tooth

 

This AOE results in smoother operation, reduces the piston breaking on the large initial pick up tooth

but as the piston is further back and the volume of air it can pull & compress is slightly reduced

it is quite common to lose a little power or fps - aprox 10-15 fps

 

so if your site is running at say 330 limit then maybe do AOE with a couple of sorbo pads

and acheive same result but will run smoother

 

http://www.ebay.co.uk/itm/Neoprene-Rubber-Penny-Washers-Adhesive-Backed-M4-M5-M6-M8-M10-M12-SN0001-/250981193606?pt=LH_DefaultDomain_3&var=&hash=item801394491d

 

is what I use - M4 hole size & 20mm outer diameter (cylinder bore is aprox 23.8mm so 20mm is ideal)

there are others but you want self adhesive washers, aprox 2mm thick

might need just 1 or 2 might be a bit too much

they go on cylinder head - not piston head

 

google it and watch some vids, it is one of the tweaks most recommend but often lowers fps a tiny bit

not a massive operation at all to do

yes some say it should be this grade or that grade of rubber but does the job for me

[Lt Earholes]

My site target is 330 but 350 max, with the ten shots I do for the chrono 1 or 2 go over 350 so want to drop it down abit.

Yeah spring is an element one, compared to my old spring it is slightly longer and does seem a few thou thicker.

When I first compared it I did think, shouldn't this be thinner or shorter.

I'll have a watch of some videos and some research into it.

[Sitting Duck]

Don't worry about any of it - it is working so leave it as it is

thought you might be on a 328/330 cqb site

But as they allow up to a 350 max - same as mine and it is the absolute max at mine

 

Anyway they allow up to 350 - you are at 345......

 

in say a month or two it is very very likely it will drop a bit - all springs lose their tension over time

so really don't worry about it coz you won't be hitting that in 3-6 months time

 

often when guns may start to drop to under 300 say then it might time to tweak / service / check seals blah blah blah

until then don't worry if you just scrape under atm, very likely won't last that high

 

it is hard to say but for all we know you could got a M150 or something

though I think you would of noticed the difference when fitting

(it would of fought back a bit putting in box)

could be a M130 and stock motor says f*ck this for a game of soldiers

who knows - no real way of telling without testing it

but a slim chance it could something else other than a M95

 

its working & leave it as is - coz 345 is ok and it will decrease a bit

[RR01]

The other thing to try is cycling the gun in auto so that the piston stops part way through the cycle and remains partly compressed. Leave it like that for 48-72 hours and you will find the spring will loose a little bit of its tensile strength, like cutting about half a coil off the spring. Then retest on the chrono. At your site you probably want to aim for an average of 338 with a max / min of +/- 5 FPS, which should keep you safely under the site limit. I once did this by mistake and left a spring half cocked for two months and lost about 60 FPS initially, but continued use then saw that climb back up to a loss of about 20 FPS overall.

[Lt Earholes]

Cheers guys, gonna try the method RR01 said and leave it at that then.

[Lt Earholes]

The other thing to try is cycling the gun in auto so that the piston stops part way through the cycle and remains partly compressed. Leave it like that for 48-72 hours and you will find the spring will loose a little bit of its tensile strength, like cutting about half a coil off the spring. Then retest on the chrono. At your site you probably want to aim for an average of 338 with a max / min of +/- 5 FPS, which should keep you safely under the site limit. I once did this by mistake and left a spring half cocked for two months and lost about 60 FPS initially, but continued use then saw that climb back up to a loss of about 20 FPS overall.

Done the half cycle method and it was still around 340 dropped about 5 fps, so I adjusted the hop ever so slightly now it's running around 335.

So cheers for that lads, should be all sorted now ready for the first game of the year, hopefully Saturday.