Issue after upgrades

[sab567]

Hi everyone who want to help me.

Firstly the airsoft is an G&G GR25, using a standard V2gearbox with a longer noozle. I worked on it since 2 beautifull year, and now here is a huge issue that I tried to solve since a week.

So here it is, I bought a Modify piston (to replace my old Madbull) and ajust the AoE with sorbo pad. I bought a Modify 0 type cylinder too. I change it, close the gearbox and there is a first problem : gearbox have a hard time to cycle proprely, using a 11.1V (nothing move with a 7.4V) and have a bad FPS (140fps with 0.25g).
Open again, after few time I measure difference in size of the new VS old piston, rail to rail, and there is the modify have 0.3mm larger (Sand it, now it move freely il the gearbox). Close it again, and it's worse, now NOTHING move (7.4V nothing, 11.1V fuse blown). Open it, all look good to me... no idea of the problem.
The compression is REALLY GOOD (maybe too much), if you put your finger at the front of noozle, the piston will not move foward
I tried an other motor, nothing more

There is my To DO list:
-Sand again the piston
-Try old piston
-Try old cylinder
-Take a look to the shimming
-Take a look to the engagement of pinion gear
-Take a look to the AoE again (maybe the piston engage badly?... doupt but)

DONE list:
-Take a look to the motors connectors --> OK
-Take a look to all the connections --> OK
-Try to run the gears with the motor, without piston --> Ok, work find


DO YOU HAVE AN IDEA OF THE PROBLEM?!?!?

For curious, there is my actual internal setup
-6.03 Promy barrel 510mm (Have a JBU 650mm 6.01 too in back up) with R-hop
-M110 Madbull Spring
-MOSFET (with outside of the gearbox wiring) with DEANS
-Old piston : Madbull half theet
-Old cylinder (Stock)
-New piston : Modify ultra-high speed
-New cylinder : Modify 0 type
-Modify piston head
-G&G stock gears, motor, tappet plate

[ThunderCactus]

if you take the anti reversal latch and piston out and close the mechbox with all the screws in place, do the gears spin freely?
Is the motor pushed up too high into the gears?

Did you make any changes to the barrel or hopup?
And when you assemble the gun, look down the barrel with a flashlight and see if the air nozzle is centered to the barrel. It's difficult but it can be done.

[sab567]

Originally Posted by ThunderCactus

if you take the anti reversal latch and piston out and close the mechbox with all the screws in place, do the gears spin freely?
Is the motor pushed up too high into the gears?

Did you make any changes to the barrel or hopup?
And when you assemble the gun, look down the barrel with a flashlight and see if the air nozzle is centered to the barrel. It's difficult but it can be done.

-Without anti-reversal, motor and piston the gears spin freely like a charm.
-Motor ajustement will be to check, but never has problem before, same as the bevel gear shimming. I'll try to ajust it all this afternoon.

-Didn't change the barrel/hop-up for now.
-I'll try to check if the nozzle is centered to the barrel, but it can't fix the "non-moving" gearbox issue, as I don't have to assemble all.

My first theory of the low FPS and low trigger response was a resistance on the piston (That was true and solve with sanding the rail on the piston).

[ThunderCactus]

You're still getting low fps and good compression with the stock piston, right? So it might be a mechbox alignment issue.
Also, does your air nozzle move back and forward freely with the mechbox closed?

You could also take the piston out, and run the gears with the motor to make sure the gear train runs properly.

[sab567]

Originally Posted by ThunderCactus

You're still getting low fps and good compression with the stock piston, right? So it might be a mechbox alignment issue.
Also, does your air nozzle move back and forward freely with the mechbox closed?

You could also take the piston out, and run the gears with the motor to make sure the gear train runs properly.

-Didn't try the old piston at this time, it's on my To Do list. Maybe it'll fixt my problem or let me know where the issu is comming from (to big piston, restriction, or something like that)
-As I saw, the low FPS is related with the low trigger response (Before my trigger response was really fast). Like a big restriction to pull back the piston and hard to push it too, like I said the rails on piston was too large at the start and I sand it to solve this problem.
-I'll try to run the gears with motor without the piston. I'll let you know

[sab567]

Without piston, spring and spring guide, the gearbox run without problem as it's possible to see.
So the trouble look's to come from piston/cylinder and this part of the assembly

Ok last test done, I put the stock G&G piston in it, and all work perfecly.
So there it is, the modify piston look to have an issue... but I don't find what exacly at this time.

[ThunderCactus]

THOSE DAMN MODIFY PARTS.
I'd recommend just getting a new piston, like a lonex, or systema

[slowbird]

I wonder what the problem is with the modify piston?

[sab567]

Originally Posted by ThunderCactus

THOSE DAMN MODIFY PARTS.
I'd recommend just getting a new piston, like a lonex, or systema

Yeah I'll go with an other brand.
It's someone who recommended me the Modify piston... bad Idea at the finish line I think.