Gearbox help

swiftblade

I have this weird thing I can't for the life of me figure out.

When the gun is cycled on semi, when it comes to rest the tappet plate and air nozzel isn't fully forward. It's like it's not resting in the right position. This is resulting in crazy low FPS, because it's not fully forward into the hop up unit. All the springs are in place on the tappet plate, so it isn't that.

Any ideas? It's an Ak (V3) gearbox.

DeBurca

Have opened the gearbox or replaced any parts inside ??????

swiftblade

DeBurca wrote: »

Have opened the gearbox or replaced any parts inside ??????

Opened it up, replaced spring and air nozzle and re shimmed.

T4RGET

swiftblade wrote: »

Opened it up, replaced spring and air nozzle and re shimmed.

you may have the wrong air nozzle installed or not installed it properly

swiftblade

T4RGET wrote: »

you may have the wrong air nozzle installed or not installed it properly

Nope that's all OK. When I open the gearbox up replace everything right, set the timing, then close it back up, I can push the air nozzle back in and springs back out. But when fired, it comes to rest in like a halfway position.

Inari

Is your piston moved back at all? As unusual as it is, it sounds like you have overspin on the gears, that the tappet plate is being pulled back by the sector gear after a full cycle.

It is very irregular to have this problem. Does it occur outside of the body? V3 gearboxes are handy to work on because of the motor cage - you can test them a lot more thoroughly before assembling the gun.

When did the problem begin? Did you replace any parts in the gearbox, or do any maintenance work on it?

swiftblade

0

Inari wrote: »

Is your piston moved back at all? As unusual as it is, it sounds like you have overspin on the gears, that the tappet plate is being pulled back by the sector gear after a full cycle.

It is very irregular to have this problem. Does it occur outside of the body? V3 gearboxes are handy to work on because of the motor cage - you can test them a lot more thoroughly before assembling the gun.

When did the problem begin? Did you replace any parts in the gearbox, or do any maintenance work on it?

When I open the box, the piston is under a tiny bit of tension. Yup, it occurs outside the body. Just replaced the spring in it.

Could over spin create low FPS, as iv'e read esle where tht it's not really a major problem? Should I be looking somewhere else regarding the low FPS? I had it in my head that because it wasn't fully forward, it wasn't engaging properly with the hop up. But If it is overspin then it completes a cycle as normal anyway?

Inari

It shouldn't really be affecting FPS, as the air nozzle will return forward once its clear of the sector chip, but if it's overspinning it will just be pulled back after completion. So it's just one thing that's going on.

Is it moving at all during the cycling of the gearbox? If I were you I'd remove it from the body, and just test the crap out of it outside of the gun. You should be able to see more clearly what is going on with the gun.

Did you replace the spring, or cut the spring?

PS: Your cylinder's not ported is it? And if so, is it correct to the barrel length, and orientated correctly?

swiftblade

Inari wrote: »

It shouldn't really be affecting FPS, as the air nozzle will return forward once its clear of the sector chip, but if it's overspinning it will just be pulled back after completion. So it's just one thing that's going on.

Is it moving at all during the cycling of the gearbox? If I were you I'd remove it from the body, and just test the crap out of it outside of the gun. You should be able to see more clearly what is going on with the gun.

Did you replace the spring, or cut the spring?

PS: Your cylinder's not ported is it? And if so, is it correct to the barrel length, and orientated correctly?

Thanks Inari for all this help.

It's moving fine the nozzle and tappet plate. It's feeding fine too. It was just the fact that it wasn't resting in the normal position that scared me.

The spring was replaced. It was a drilled nozzle originly with a stronger spring. Both replaced to downgrade properly.

Nope, cylinder isn't ported. The only other thing I can think of is, it's a hop up issue. The compression in the cylinder is fine (tested out of gearbox, finger over the end, etc.)

Inari

It's your air nozzle then, I'd be quite sure of it.

Measure it against the drilled one. Is your AK a DBoys? If so then it is DEFINITELY the nozzle at fault. In work we had a nasty repair where the air nozzle had been replaced by another tech, but most V3 nozzles are a couple of mm shorter than the stock DBoys one, and as a result massive air leak. As in we put in an m120 spring and got 0.27J on the chrono. It did 0.26J with an M85...

Eventually we got to the bottom of it, but yeah, I would definitely recommend checking the nozzle against the stock one

swiftblade

Inari wrote: »

It's your air nozzle then, I'd be quite sure of it.

Measure it against the drilled one. Is your AK a DBoys? If so then it is DEFINITELY the nozzle at fault. In work we had a nasty repair where the air nozzle had been replaced by another tech, but most V3 nozzles are a couple of mm shorter than the stock DBoys one, and as a result massive air leak. As in we put in an m120 spring and got 0.27J on the chrono. It did 0.26J with an M85...

Eventually we got to the bottom of it, but yeah, I would definitely recommend checking the nozzle against the stock one

Will check it now and report back in a few mins.

swiftblade

Thought it would be easier to just take a picture. Old on the left, new on the right. it looks to be a fraction smaller, but not even noticable. You think it could be the problem?

THE MINDER

swiftblade wrote: »

I have this weird thing I can't for the life of me figure out.

When the gun is cycled on semi, when it comes to rest the tappet plate and air nozzel isn't fully forward. It's like it's not resting in the right position. This is resulting in crazy low FPS, because it's not fully forward into the hop up unit. All the springs are in place on the tappet plate, so it isn't that.

Any ideas? It's an Ak (V3) gearbox.

Thats not unusual and it has no detrimental effect so dont worry about it:)

krzyfu

1.
You made reshimmed this gearbox. Remowe pneumatic and spring, fit all scrwes and check gears, should working smooth and easy.
2.
Your new air nozzle is shorter like old one.
3.
Check how sliding air nozzle on piston head pipe, should by smooth. Check small oring iside air nozzle
4.
Check oring on piston and cylinder head
5.
I can fix this problem.
6.
SPRING M120 IS VERY STRONG IF EVERYTHING WORKING CORRECTLY GUN SHOULD SHOOTING ALMOST 2 JOULES!!!!

Southern Dandy

krzyfu wrote: »

1.
You made reshimmed this gearbox. Remowe pneumatic and spring, fit all scrwes and check gears, should working smooth and easy.
2.
Your new air nozzle is shorter like old one.
3.
Check how sliding air nozzle on piston head pipe, should by smooth. Check small oring iside air nozzle
4.
Check oring on piston and cylinder head
5.
I can fix this problem.
6.
SPRING M120 IS VERY STRONG IF EVERYTHING WORKING CORRECTLY GUN SHOULD SHOOTING ALMOST 2 JOULES!!!!

KRZYFU indeed....:D

swiftblade

krzyfu wrote: »

1.
You made reshimmed this gearbox. Remowe pneumatic and spring, fit all scrwes and check gears, should working smooth and easy.
2.
Your new air nozzle is shorter like old one.
3.
Check how sliding air nozzle on piston head pipe, should by smooth. Check small oring iside air nozzle
4.
Check oring on piston and cylinder head
5.
I can fix this problem.
6.
SPRING M120 IS VERY STRONG IF EVERYTHING WORKING CORRECTLY GUN SHOULD SHOOTING ALMOST 2 JOULES!!!!

I never mentioned an M120