JG HK416 not firing

[Andres]

Well, being the captain of "do-it-yourself," I decided to install a MIAD Pistol grip on my 416, as well as attempting to put an M4 sling adapter onto the stock (which may have caused the problem enitially... turns out the adapter doesn't work because it's missing a space to let wires through, so I almost ripped the wire in half before I realised there was no space for it DX).

Basically, I installed the pistol grip and the motor may be messed, I'm not sure. After the pistol grip was installed, the two wires connecting to the motor were installed correctly (Red to red, black to blank space[or maybe this is wrong, and you've just solved my problem already]), threw a battery into the stock and shot, then it went (my favorite noise... ) "REEEEERN" and just stopped dead.

If this involves replacement of any internals I'll be sure to have a local gun-doc take care of it, however, if there's an easier way about this... feel free to shoot me (no pun intended) some ideas on what the hell I did wrong.

[Styrak]

Uh. What sound does it make now when you pull the trigger, just a buzz from the motor?

[Andres]

No noise at all.

[COBRA-CC]

check your motor one of the leads may have came of and check your fuse too

[jesster202]

check fuse as stated check motor, then check if the wireing to the fuse box is connected if not then its messed than go see a gun dock.

[Andres]

Will do, thanks for all the help... will return later with results, bit busy with something else at the moment!

[Dynamo]

your problem is real simple.
the magpul MIAD grips have a design flaw that magpul overlooked.
befor i get into further detail, check to see it your motor is still alive.
remover your motor from the grip and reconnect the wires, then pull the trigger and see if it still runs. if it doesnt run, well you are going to need a new motor.

ok if your motor does still run then good, i can now explain to you what is wrong with the MAID grip and how to fix it.
the problem with the MAID grip is its end plate motor hight adjustment screw housing(the brass part molded into the end plate).
the problem here is that magpul screwed up and didn't design the screw housing with the needed recess for the endbell of the motor(the bottem of the motor that holds the bearing for the motor shaft). this causes the motor to sit on the endplate and not on the hight adjustment screw, which makes the motor sit far to high(causes the "REEEEERN" sound you described).

now for the fix.
you are going to need some tools to remove material from the inside of the screw housing, a dremel or even a drill.
basically you are going to make that recess that magpul forgot to make.
you will need to remove enough material(about 2mm), and expand the diameter to 10mm. after that make sure that the endbell fits inside the newly created recess, and then reassemble the grip with the motor inside.
now you will be able to adjust the motor hight adjustment screw properly.
*note: the hight adjustment screw does not have any means of staying in the position you set it to, due to the motor vibrations it will unscrew and lossen, lowering your motor. you will need to use some loctite thread locker to keep this from happening, after that you should be good to go.

hope this helps.

[Andres]

And I thought it a comfy pistol grip woulda' been easy. Thank you very much for your input, highly appreciated.

[jesster202]

crap i rember i had that same problem whith my new grip i just did the same thing

[m102404]

Originally Posted by Dynamo

your problem is real simple.
the magpul MIAD grips have a design flaw that magpul overlooked.
befor i get into further detail, check to see it your motor is still alive.
remover your motor from the grip and reconnect the wires, then pull the trigger and see if it still runs. if it doesnt run, well you are going to need a new motor.

ok if your motor does still run then good, i can now explain to you what is wrong with the MAID grip and how to fix it.
the problem with the MAID grip is its end plate motor hight adjustment screw housing(the brass part molded into the end plate).
the problem here is that magpul screwed up and didn't design the screw housing with the needed recess for the endbell of the motor(the bottem of the motor that holds the bearing for the motor shaft). this causes the motor to sit on the endplate and not on the hight adjustment screw, which makes the motor sit far to high(causes the "REEEEERN" sound you described).

now for the fix.
you are going to need some tools to remove material from the inside of the screw housing, a dremel or even a drill.
basically you are going to make that recess that magpul forgot to make.
you will need to remove enough material(about 2mm), and expand the diameter to 10mm. after that make sure that the endbell fits inside the newly created recess, and then reassemble the grip with the motor inside.
now you will be able to adjust the motor hight adjustment screw properly.
*note: the hight adjustment screw does not have any means of staying in the position you set it to, due to the motor vibrations it will unscrew and lossen, lowering your motor. you will need to use some loctite thread locker to keep this from happening, after that you should be good to go.

hope this helps.

Great stuff already written...

Just a note or two:
- I've only had one Magpul MAID grip myself, but have installed 2 others...and have not noticed the clearance problem described. Mine is currently installed with a Systema Magnum motor and previously with a EG1000. One of the others that I've worked with was with an EG1000 and the last with a JG motor (whatever that is).
NOTE: I think I get what you're describing, but if you could post a pic I'd love to see what you're talking about. Maybe I've just lucked out on motor/grip/heatsink combos I've come across.

When installing any heatsink, you do have to ensure that the motor is actually being adjusted by the motor height screw. Sounds too simple, but I've see plenty of instances where the motor isn't "freely moving"/"springy" in the grip.
- Take care to make sure that your motor wires are nicely routed and not binding up the motor movement. With both wires connected, you should be able to lightly push the motor deeper (all the way) into the grip and have it spring back freely.
- take care when putting the heatsink on the grip that any ball bearing/plate that should be there, is there (MAID one doesn't have anything, KA G27 has a ball bearing, stock TM grips have a little plate/disk, etc...). If you're having a really hard time with ball bearings or plates/disks getting out of place, you can cheat with just a touch of crazy glue to hold it in place until you get everything mounted (not normally necessary, but the systema magnum motor seems to suck anything metal straight up into the grip and then you have to take the motor out to get it back).
- Note the wiring that routes over the top of the motor and attaches to the -ve/+ve terminals. Quite often they'll get caught up and pinched between the heat sink and the motor, artificially raising the height of the motor. They can also get in the way of the grip screw holes (the black one especially), but that's easy to see since it'll block the hole (still a pain to reseat the heatsink).
- I've found that with most setups with thicker wire (i.e. 16/18AWG), that when the wires are connected to the motor connectors they point straight across the motor and getting them to clear the heatsink can be a bitch. If you !!!gently!!! turn the connectors so the wires are slightly angled away from the center of the motor, it'll be easier to get the heatsink on. Don't snap them off though or you'll be FUBAR'd.

Here's what I do to adjust the motor height....this is just what I do and others may have their own way which is totally good if it works for them.
- Once you have everything installed and screwed tight, check that the motor is actually moving with the adjusting screw. Screw it in and you should "feel" a little resistance from the motor pushing back against it. Screw it out and you should "feel" a little resistance as well. Keep screwing it out and you should feel a point where you're just turning the screw and not moving the motor at all.
- screw the adjustment screw all the way in. Don't go nuts, just screw it in until you feel like it is meeting too much resistance. That's you're motor bottoming out. If you were to fire the rifle now, you would just get a dead "thunk" and the motor probably won't turn.
- back off the screw at least 2 full revolutions. Put the rifle in single (NO BBs) and pull the trigger (don't feather the trigger, don't hold it down, just 1 good pull). It may fire or it will give you a dull "thunk". (if you don't get some kind of "thunk" sound, check that you haven't blown a fuse).
- If doesn't fire, back off the screw another full turn and try again. Keep going until it fires. If you go through this over and over and eventually the motor makes a "schreeee" noise...stop, there is something else wrong with you mechbox/setup (make sure your battery is fully charged)
- When it does fire, it probably won't sound great (i.e. a little screechy/rough). Back off the screw a quarter turn at a time. It'll get "deader" and then noisy again. Screw back in, a quarter turn at a time, until it sounds it's "deadest"/quietest. That's the ideal setting.
- To lock the ideal setting in place, back the screw off at least 2 full turns (or in if you're running out of adjustment), place a drop of BLUE Loctite on the threads and screw it back in the same amount that you backed it off.
- Test to confirm and you're done.

Good luck, best of luck getting sorted out!

Tys

[Flatlander]

BE VERY CAREFUL WITH LOCTITE ON THE MOTOR SCREW. I recently did this to a buddies MIAD grip and nearly destroyed the baseplate in the process! I put a small drop of it (blue loctite) on the threads and reinstalled the screw. Once it set up it was almost impossible to get out! I wrecked the original standard screw driver slot, dremelled it deeper, and then wrecked that! I dremelled a new slot 90 degrees to the original and quite deep to get a better bite and it took literally all my strength to get the damn screw out!. Once it was out, it went back in fine with no resistance...which is weird because normally there's some residual stuff left over and give you the nice resistance I was looking for. Now it still backs itself out with the vibrations from the motor so I'm going to resort to tephlon tape once I put it back together.

I have never seen this before with blue loctite. I think it might have something to do with it being brass on brass? Anyone else experience this before?

[Darklen]

If you use locktite, use 222. It's very low strength (weaker than blue, which is 242) hold the screw while not allowing the screw to come out by it's own accord. Beware of using locktite around plastic. It can cause some plastics to weaken and break over time, particularly polycarbonate.

[Danke]

You can also use a drop of model paint to "freeze" screws.

When you do this put some sort of grease inside the head or face of the screw or bolt because if you fill that with paint you'll really be swearing when the time comes to pull it apart. The paint is something more folks will have, and it's less likely to react with the plastic the way Loctite will.

[Andres]

The bit that m102404 posted I am for sure going to try. I might be able to get pics up sooner or later, perhaps tomorrow.

[m102404]

I would concur with what the others said about blue Loctite...but would add:
- once a grip/motor/mechbox/body combo is setup and tuned, there's very little need to adjust the motor height unless one of those items are changed. So...for a lot of guys who don't fiddle with their stuff it's not so much of an issue. That's even if the motor and grip are removed for maintenance. If you have so much gear (pinion/bevel) to warrant adjustment, there is something seriously wrong.
- as with any screw, you should be using an appropriate sized screwdriver bit. Some motor adjustment screws have slots so large that all but my largest screw driver will nick the edges. (almost like they expect you to use a nickle to turn it).

I'd definitely go with some of the alternate suggestions of what to use. I.e. nailpolish, model glue, etc...I just use loctite, and always have. Maybe because the way I do it I just get a couple of threads and not all the screw threads that I've never had a real problem breaking the threads loose. Sometimes, tightening it just a touch and then loosening it breaks any "chemical"/corrosion bond that seizes threads.

Tys