upgrade problems with G&G M4.

[MALTV]

I've recently upgraded my G&G M4 and of course i have a few problems...

1. I cant seem to get the motor correctly adjusted...no matter how much i try i still hear that horrible not correctly adjusted screech from the motor.

2. I've put in a VS M110 Spring, its almost an inch shorter than the spring i took out of my gear box, will this cause problems? will i not get the FPS i'm looking for.

3. When i put a magazine into the gun and try to fire at first it wont, then it will fire one round and then it sounds like the gun is clogging up and wont fire anything.

Am i totally screwed or can these problems be fixed?

[audi_bhoy]

Don't worry, everything can be repaired in this world.

Did you change the spring yourself?
If so, did you took time to carefully replace each shim at his place on the gears?
Did you reinstall the anti-reversal latch correctly?
Did you swap anything else than the spring? Gears for example?

[MALTV]

i changed the spring myself
I did replace each shim on the gears
I'm positive i reinstalled the anti reversal latch correctly
and i replaced all the gears, shims, air nozzle, tappet plate, cylinder, piston, spring, spring guide.

I used a systema Full tune up kit.

[Azathoth]

Did you properly shim the gearbox.

Taking the shims off the each G&G gear and putting it onto the systema equivalent is not the same as properly shimming a gearbox.

[MALTV]

I used the systema gears and shims, How are you supposed to properly shim a gear? I thought i was doing it correctly but god knows i could be doing it ass backwards....

[Azathoth]

YouTube - ‪Deadman's gearbox shimming guide airsoft mechbox‬‏

I didn't watch the tutorial in detail but it's a start.

The 'proper' or near optimal clearance between gears is 0.20mm. You can find guides on airsoftmechanics or all over the place. Once you figured out the shimming you need to close the box and screw it down. Reach into the gearbox with your fingers and spin the gears with the gearbox left side down, right side down and upright in the shooting position. With the gearbox in these 3 positions the gears should spin freely and not bind. The reason why you rotate the gearbox in these directions is to make sure that you didn't under shim the box on a given side. Some people like to give a little bit of play to the bevel gear.

[MALTV]

could under greasing the gearbox also be a problem?

[Azathoth]

Possibly but if it's making that much noise I doubt it.

Without any lubrication at all, my gearbox doesn't make screeching or grinding sounds.

If you watch the video you can hear the whirrrrrr sound of the gears spinning. That box has zero lubrication on the drive train and that's about how much noise it will make when he installs the compression system

OH yeah, I don't suggest you buff down the gears like he did with a dremel.

[audi_bhoy]

Azathoth is absolutely right, each gearbox and gearset are unique when it comes to shimming, you have to do it very carefully ! Start with that, and then we'll start from there if it still doesn't work properly.

[MALTV]

Alright, so if shimmed correctly this time. I should be able to correctly adjust the motor. if you look at my main post i also ask about my spring and a firing problem I'm having. Any suggestions on how to remove these problems? is it all in the gear box or could it be something else?

[Azathoth]

I suspect that all of your problems will be resolved with a properly shimmed gearbox. Remember that the motor does not screech. It's your gear train making that noise.

You may have lost your tappet return spring and that is why your gun is not shooting.

Short of buying a PSG-1, PTW cylinder spring, VSR-10, AEG springs are universal. Their are different designs such as linear vs non linear, materials that affect how a spring will behave. Short spring is not necessarily a weaker spring. My Airsoft surgeon stage 6 springs are about 1 to 1.5" shorter than all the other linear springs I have seen but it's equivalent to M210+

[MALTV]

Originally Posted by Azathoth

You may have lost your tappet return spring and that is why your gun is not shooting.

i haven't lost it, its attached where it should be. Could it possibly be anything else?

[MALTV]

so I've re shimmed, done everything you've told me to do, I've moved the gears with the mechbox screwed shut, the gears moved freely with very very little resistance. I've reinstalled the anti reversal latch made double sure the tappet return spring was properly in place and then tripled checked everything to make sure...but its still being an ass and won't fire properly...maybe its time to seek some face to face help?

[Azathoth]

Is the horrible sound gone?

Now you are just having a feeding issue?

[audi_bhoy]

Yeah same question, I've came across some bad gears set two times in my repairs, one was King Arms and the other SHS, both helical sets. If the sound is gone, then your gears are correct.