AGM M14 gearbox/motor grinding sound

[Boogieman]

OK. I am sorry if it was answered before but I could not find it anywhere here or elsewhere. My gun started making grinding noise in the area of GB/motor. I bought it used and it was upgraded by the previous owner. He put in Matrix 3000 motor and new spring (he did not indicate which one). I have shot about 1000 rounds with it since I bought it, however, on Saturday after only 100 rounds on semi-auto it started grinding. I took it apart today but have no idea what to look for. The only thing that it seems to be not right is the motor which is not seeded in far enough per me, but I might be wrong.

Any help would be greatly appreciated!!!

(I can add pics if needed.)

[MCG]

Most likely your motor height is out of adjustment, which would cause your pinion gear to slip.

[Boogieman]

Most likely your motor height is out of adjustment...

How would I go about adjusting it?

[Villid]

theres a screw or hex head in the bottom on the grip.  just turn it the desired direction until you get the desired results.  at least thats how i adjust mine.  others screw it all the way down and then back it off slowly.

[Jeremy314]

theres a screw or hex head in the bottom on the grip.  just turn it the desired direction until you get the desired results.  at least thats how i adjust mine.  others screw it all the way down and then back it off slowly.

Sean, it's a V7 gearbox, so the motor doesn't sit nearly vertical like in V2s and 3. It's horizontal like in the P90's V6 gearbox

[Boogieman]

... It's horizontal like in the P90's V6 gearbox

Yes, it is horizontal, little bit in an angle.

[Boogieman]

Well, mine does not have any screws on it so I do not know how to adjust it. Seems like other people have had the same problem with this particular model. However, after taking it apart, I attached the motor back, it made grinding noise once and started working ok. Now I have to put the rest of the gun together. Hope it will work. 

[Boogieman]

So, yesterday I unscrewed the motor from the gearbox, stared at it, and screwed it back in. And what? It started working fine. (I guess starting at the motor helped.) While I was at it I also took apart the hop up, cleaned up my inner barrel (it was really nasty). Previously it was not shooting very accurately and I believe that cleaning will solve it. I will play on Saturday and see how it is going to perform. Thanks for all your help, guys.

[Dominum]

AGMs are innacurate because they have bad stock hopup buckings, though cleaning will help, it will not fix it. While you have it broken down all the way, you should go ahead and replace the bucking. As far as the symptoms being explained by a mounting height issue, while normally that would make sense, M14's not only have an internal set screw for motor height adjustment, but they usually come with some adhesive on it, so it is very unlikely that it was originally fine and then somehow "slipped" out of adjustment. It is more likely some other issue that was either coincidentally alleviated either temporarily or (hopefully) permanently. But then, as far as AEGs are concerned, there are many specific types of "grinding" noises to be heard, and it could have been as simple as a low battery, depending on how exactly it sounded.

[Boogieman]

... go ahead and replace the bucking.

What bucking should I buy?

[Stomper87]

I prefer Firefly, I am able to get amazing range with them, although they are a little expensive.

[Dominum]

There are plenty of good aftermarket buckings, all of which are better than the stock one, I'd read some reviews. If you can, get a firefly medium or soft buckings AND nub, if that is out of the price range, I would go with Systema.

[Gman Chris]

AGMs are innacurate because they have bad stock hopup buckings, though cleaning will help, it will not fix it. While you have it broken down all the way, you should go ahead and replace the bucking. As far as the symptoms being explained by a mounting height issue, while normally that would make sense, M14's not only have an internal set screw for motor height adjustment, but they usually come with some adhesive on it, so it is very unlikely that it was originally fine and then somehow "slipped" out of adjustment. It is more likely some other issue that was either coincidentally alleviated either temporarily or (hopefully) permanently. But then, as far as AEGs are concerned, there are many specific types of "grinding" noises to be heard, and it could have been as simple as a low battery, depending on how exactly it sounded.

The pinion gear could be getting worn out. That can cause the alignment to need adjusting. As for the bucking, I run G&P buckings in my AEGs. I've had great luck with them. And they're cheap! Lol.

[Boogieman]

I run G&P buckings in my AEGs.

Are you talking about this? http://www.airsoftpost.com/product_info.php?cPath=24_71_368&products_id=30604

[Dominum]

Nope, that is made by Element, he is talking about buckings made by G&P.