V3 Gearbox help

Leader Bee

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Sorry if i'm not quite in the right sub-forum gents but i need a bit of help.

I've got a Cybergun FN2000 which at the time of purchase I didn't realise it was calibrated for somewhere around 370 FPS, which, obviously is over the limit for being able to use it.
So the genius that I am thought how hard could it be to take apart and replace the spring?

Anyway, the gearbox basically exploded apart when I finally got the case off and I think I've now managed to find all the bits that went flying.

I'm mostly there with putting everything back together, but i've got these two last bits that I can't quite work out where they go.

Any help?

It's the silver spring and this little doohickey that looks like it might have something to do with the trigger?

Thanks!
 

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Oh damn, thanks Gavin - I could have sworn that silver spring was something to do with the trigger but I guess not, i'll have to take that back apart and move it. Thanks for the help
 
you are correct that silver spring is the trigger spring, unfortunately the v3 trigger spring can be one of the most hateful things to try and install.

the other component is the anti reversal latch, it goes into this hole:
1780163926453.webp

it drags against the bevel gear to stop the gearbox going the wrong direction and should have its own spring, although a much finer spring than the trigger spring.

you also want to pay attention to the shims, circled in yellow, which are for spacing the gears left/right in the gearbox casing and stopping them from rubbing against other components/each other.

usually the best practice if you don't want to re-shim a box is to make sure you keep them where they were before you opened it up, but sadly this opportunity may already be lost.

i had a tutorial that covered some of the box assembly with a v3 box but alas it seems the pictures didn't survive the forum upgrade making it kinda useless if you don't know the names of different bits. but there is this thread that has some links and discussion for shimming:

Those are the anti reversal latch & it's spring.

looks more trigger spring to me, far too heavy for an arl.

possibly the trigger has been installed with the arl spring instead?
 
you are correct that silver spring is the trigger spring, unfortunately the v3 trigger spring can be one of the most hateful things to try and install.

the other component is the anti reversal latch, it goes into this hole:
View attachment 31030

it drags against the bevel gear to stop the gearbox going the wrong direction and should have its own spring, although a much finer spring than the trigger spring.

looks more trigger spring to me, far too heavy for an arl.

Ahhhhhhhh Thanks for pointing that out, I nearly forgot about that little piece, it was a tiny black spring that was almost invisible against my mousepad, found it! Still not worked out exactly how it goes back together but yes, I've tried to get that bastard little trigger spring back in place but it's being a real pain in the arse.

The trigger seems to re-set to its starting position just from the tension from a spring just under the trigger assembly, or maybe the tappet spring though, so i'm not really sure what the tiny silver one is really doing..

Thanks for the advice guys, I've gone from thinking i'd ruined a gearbox to being reasonably confident I can put it back together.

Not sure it's going to work when i've done it, but I think i'm going to head to a local airsoft shop next week to see if I can get a spring with a lower FPS so that my gun is legal for a game I have next Sunday.

I was also thinking about upgrading the piston to a steel one? I can't believe these guns come with something that has plastic gears!
 
Most pistons are plastic, often with steel teeth underneath but not always; very common and normal. Pretty sure a steel piston is not usually recommended by most folks in the know, could batter the cylinder head and in turn weak front area of the gearbox casing.
 
A plastic piston is best; you can get them with plastic teeth or metal teeth. I quite like plastic teeth on the piston; I see them as being a sort of mechanical fuse. A metal rack failing can cause a lot of damage.

If you are going to change the piston, please learn how to check and set up the Angle of Engagement.

View: https://www.youtube.com/watch?v=uWkSjIDqUBA
 
Ah sorry, yes I mean tthe teeth specifically, it just seemd a little less durable being entirely plastic
They are slightly less durable, but I have guns that have had the same pistons in them for a very long time. A well set up gearbox will not cause undue wear on a plastic toothed piston. A badly set up gearbox can cause damage to a metal or plastic toothed piston; the former send bits of metal whizzing around inside the gearbox, often damaging the gears, while the latter just sends bits of plastic.
 
Right, well I think i have this thing put back together now folks, thanks for your help.
I've orderd an M100 Spring to hopefully bring my AEG in line with the site limits, I don't know what it came with stock but the box say s 1.4 joules and 377 FPS*, so going to assume it wouldn't have been site legal.

I was going to go for a 105 but didn't want to risk bringing it even slightly over after all i've been through with this thing exploding on me when I opened it up.

Just one thing.

When the spring is sat under compression on the spring guide, there is a slight bend in the middle of the spring (just the way it collapses, i haven't damaged it) is this normal? I can't seem to get it exactly straight while it is sat in the piston.
 
When you disassembled the gun, was there a screw that went into the back of the gearbox and the spring guide? If there was, that should pull it tight and straight.
 
When you disassembled the gun, was there a screw that went into the back of the gearbox and the spring guide? If there was, that should pull it tight and straight.
Yes there was, I didn't realise thats what it was for - i'd seen you could adjust spring power with it but with the housing on it didnt occur to me at all that it would straighten it out! Derp!

Oh well, this has all been a great learning experience (if it actually works when i put it all back together!)
 
Yes there was, I didn't realise thats what it was for - i'd seen you could adjust spring power with it but with the housing on it didnt occur to me at all that it would straighten it out! Derp!

Oh well, this has all been a great learning experience (if it actually works when i put it all back together!)
I am not convinced that the spring power can be adjusted using the screw on that gun, but I have never had one of them.
 
That was the G&G F2000 that had the adjusting feature, iirc.
I've no idea if the cybergun copied that or not, bit I don't think so.
 
That was the G&G F2000 that had the adjusting feature, iirc.
I've no idea if the cybergun copied that or not, bit I don't think so.
Looking at the photo that was posted, it does not. I think Cybergun used at least two OEMs (G&G, which was the better one, and CYMA) and possibly three (JG?).
 
Ahhhhhhhh Thanks for pointing that out, I nearly forgot about that little piece, it was a tiny black spring that was almost invisible against my mousepad, found it! Still not worked out exactly how it goes back together but yes, I've tried to get that bastard little trigger spring back in place but it's being a real pain in the arse.

you have my sympathies, sadly there's no real advice on how to do it you just sorta get a feel for it.

some boxes are well enough behaved that once you get the trigger seated properly it'll stay put, others less so. i had a jg box that i ended up tapping a tiny bolt into the trigger to keep it held in place, although that comes with its own issues of weakening the trigger which can break.

The trigger seems to re-set to its starting position just from the tension from a spring just under the trigger assembly, or maybe the tappet spring though, so i'm not really sure what the tiny silver one is really doing..

in semi-auto the trolley is kicked up and over the trigger by the cut off lever to disconnect it, so the trigger needs its own return spring.

Not sure it's going to work when i've done it, but I think i'm going to head to a local airsoft shop next week to see if I can get a spring with a lower FPS so that my gun is legal for a game I have next Sunday.

if you're thinking of going down the route of doing your own tech work, then a wise investment would be to get a chrono so you can check the gun before taking it to a game day.

you can not only check the energy is kosher but also use it to spot consistency issues that'd lead it to shooting like shit without needing to test fire outdoors (which may or may not be a viable depending on your home situation)

I was also thinking about upgrading the piston to a steel one? I can't believe these guns come with something that has plastic gears!

there are reasons to have a piston that's primarily or entirely plastic, it's the same reason you'll see a lot of rc cars have a plastic gear in their drivetrains. it's an intentional weak point as a sacrificial part. idea being if something goes wrong then mincing a cheap plastic piston is preferable to mincing the whole geartrain.

that said, steel racked pistons are very common aftermarket tweaks, although tbh it's just as viable for the rack to get ripped right out of the piston.

I've orderd an M100 Spring to hopefully bring my AEG in line with the site limits, I don't know what it came with stock but the box say s 1.4 joules and 377 FPS*, so going to assume it wouldn't have been site legal.

I was going to go for a 105 but didn't want to risk bringing it even slightly over after all i've been through with this thing exploding on me when I opened it up.

fingers crossed, although don't be surprised if the energy isn't what you're expecting. springs being a bit off from their rated power is not uncommon as is straight up mis-labelling.

after a while you build up a box o' springs so you just try different ones until you get the energy you want, or settle on a brand/rating that works for your build style.

When the spring is sat under compression on the spring guide, there is a slight bend in the middle of the spring (just the way it collapses, i haven't damaged it) is this normal? I can't seem to get it exactly straight while it is sat in the piston.

as @Colin Allen says, the spring guide might be sitting wonky until its tightened into the casing. a test is you can use a flat-ended tool through the nozzle to push the piston back and feel how freely its moving and if the spring is binding. it's somewhat normal to have a little bend under tension and as long as the spring isn't bent permanently (ie when you remove it and it's not under tension it straightens out) then you're fine.

Yes there was, I didn't realise thats what it was for - i'd seen you could adjust spring power with it

that's the g&g version, which was the og pattern of f2000 that cybergun licensed that used a version 6 gearbox.

it wasn't a very good feature, sounds great on paper but the reality is you'd get eyebrows raised at every site that heard the power could be adjusted thinking you'd be using it to cheat chrono when the reality was that it would more often than not come undone mid-game and the power would drop as you fired it. although granted it did make working on the gearbox a hell of a lot easier.

couple that with the horrendous rube-golberg trigger mechanism that you could never get to fire semi properly and have fun replacing that shit when it broke and the cutoff lever was its own special kind of engineering failure. imo cyma and jg made the right move dropping a standard v3 box in there.

externals were nice, although i've not spent any time hands on with the cyma/jg to say if there's much real difference.
 
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