V3 Gearbox help

[Leader Bee]

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!

 

[ButcherBill]

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

 

[Leader Bee]

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

 

[Adolf Hamster]

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:


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:

Thread 'Pinion to Bevel Shimming'

Oct 9, 2020

I had the CA M15 open the other day - I run a Lonex ultimate GB and an A3 motor inside it (So maybe not so CA any more.. though that's how it started off life). I noticed that the pinion gear was starting to see a little wear - nothing that will take it out of action any time soon however it will certainly die eventually if it carries on getting gnawed like that.
 

Honestly the shimming in the Lonex is really good, I made a literal single shim swap around on the spur gear to space out the spur and sector a tad, but that was it, best shimmed GB out the factory I've ever seen. 

I...

• Zarrin
• Replies: 23
• Forum: Tutorials

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

Click to shrink...

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

possibly the trigger has been installed with the arl spring instead?

 

[ButcherBill]

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

possibly the trigger has been installed with the arl spring instead?

Click to shrink...

Good spot.

 

[Leader Bee]

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.

Click to shrink...

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!

 

[TheFull9]

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.

 

[Colin Allen]

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

 

[Leader Bee]

Ah sorry, yes I mean tthe teeth specifically, it just seemd a little less durable being entirely plastic

 

[Colin Allen]

Ah sorry, yes I mean tthe teeth specifically, it just seemd a little less durable being entirely plastic

Click to shrink...

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.

 

[Leader Bee]

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.

 

[Colin Allen]

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.

 

[Leader Bee]

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.

Click to shrink...

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!)