JG mechbox problem - help needed

[impi]

BB's fired just seemed to drop at about 5 meters. Then the gun stopped firing altogether. I initially thought it was the battery until i replaced it. After removing the grip i noticed that there was power coming to the motor, but that it seemed stuck.
I unscrewed the 2 screws connecting the motor to the mechbox and took out the motor. When i pulled the trigger, the motor spun freely, but after re-inserting the motor again, the motor refused to budge.

Any idea what might be causing this and how it can be fixed?
Keep in mind that I'm new to the sport and have never opened a mechbox.

[krobinson103]

Your piston head or piston have been damaged. Its an easy thing to fix. I'm guessing (without looking) that the piston head screw has come loose causing your problem.
Bring it to the next game and I will fix it for you.

[nexus]

I think I know that motor problem. if it is the JG AK and my guess is right the screw on the grip is causing the motor failure. don't screw it tightly or use shorter screw then it will work fine. But make sure that gears's teeth meet properly.

[ackme]

The motor doesn't affect the velocity. Kelly is probably right about the piston head.

If the head came off the piston itself would still have moved for a bit until the head jammed, causing it to shoot pathetically until the jam. In which case the cylinder could have been damaged, the head or the piston itself could get damaged, or it could work perfectly when the head is screwed back on.

It could also be the piston itself broke causing it to short stroke before pieces jammed in the gears. In which case all that would need to be changed is the piston itself.

If it were the gears, gear spacing, or motor, it would shoot slowly (cyclic rate), make grinding noises, or not shoot at all. But each shot coming out would still shoot at the FULL fps as this would not affect the compression. From the description of what happened it would have to be something with the compression chamber which would be the piston or head. Both wear out over time are cheap and easy to replace. Best case is that the head came off and jammed the piston, there's a good chance then it will work fine if the head is just screwed on. Too bad it's an AK, those things are a bitch to get the gear box out of (I've worked on AK's three times).

[krobinson103]

Apart from arriving as a puzzle box it was an easy fix. First the pinion gear was showing a lot of wear so it got replaced. Second, the piston head had some bearings behind it that spaced the spring back a bit. this has caused problems for me in the past so I removed all but one washer. Third, the piston head and cylinder were dry of any grease at all. This means that the piston often locks back against the small hole cut in the cylinder.

After replacing the pinion gear and making sure the spacing and lubrication were good it fires without a problem. One thing though, please don't send a gearbox like that. Its much easier if it arrives as a unit. They don't care or even know what it is.

[impi]

Thanks.
My particular post office though has a habit of asking to see what is in the box and then refusing to send anything that resembles a gun. Even a mechbox. Reggie got turned away the first time when he wanted to post it. I had to do some serious convincing when we were there the last time.

[krobinson103]

weird, when I sent the m4 they just looked at it, said "toy" and that was it.

[Righteous]

As I found out in the airport there is a wide range of interpretations about what is allowed and it varies by Customs Officer and agency. The EOD guy was fine with everything I had. One Customs Agent said none of it was allowed. The police officers said I could have it since I am SOFA. It just depends upon whom you get.