2 LCT AKs - Neither will work out of the box.

[Oshiha]

For the AK74, are you using a 9.6v Nimh? Try a 7.4 and see if that will turn the motor. I have this problem on one of my guns where a 9.6 wont turn it, but a 7.4v lipo will

[Latvian291]

Thanks for the help. I have some idea now what to look for when I open them up.

[lurkingknight]

other possibility is that it compression jammed at some point and the gears are stuck halfway into the piston's forward cycle so it's advanced a number of teeth, which would mean the piston would be all the way at the rear of the gearbox with the sector gear with more teeth to rotate through.

You'd have to pull the gearbox apart at that point to find it though. But it also would produce a motor click sound as it tried to cycle with the gear jammed.

[Latvian291]

Originally Posted by lurkingknight

other possibility is that it compression jammed at some point and the gears are stuck halfway into the piston's forward cycle so it's advanced a number of teeth, which would mean the piston would be all the way at the rear of the gearbox with the sector gear with more teeth to rotate through.

You'd have to pull the gearbox apart at that point to find it though. But it also would produce a motor click sound as it tried to cycle with the gear jammed.

Excellent suggestion. This is possibly the most helpful response so far.

[Latvian291]

Problem with the AK-74 fixed. It turned out the tappet plate had been installed incorrectly at the factory. It was behind the sector gear causing complete lockup. It was slightly damaged but on the side that doesn't engage any parts, so I installed it properly and voila!
Will post pictures later.

Now to attack the AIMS.

The problem with the AIMS it turns out was a badly formed copper connection terminal. I bent it to an acceptable shape and it started working again. The only problem was the sector gear somehow got in behind the tappet plate, like on my AK-74, and this time the sector gear destroyed the tappet plate completely. Any ideas on the cause? I am working on posting pics right now.

[Latvian291]

AIMS:


AK-74

[boren93]

Well thats weird my piston in my ak74mn is the clear one.

[Latvian291]

I almost think the problem with the tappet plate may be from releasing the anti reversal latch to open up the gearbox. Is that possible? It looks like the sector gear turned into the tappet plate really hard and then jammed the gearbox.

Why is the back of the tappet damaged?

[lurkingknight]

I've had it happen once... compression jam and it jumped the shim and jammed itself behind the tappet fin. not sure exactly how it flipped, I'm thinking it wedged itself deeper than what you have it. but it looks almost exactly the same.

[Latvian291]

Originally Posted by lurkingknight

I've had it happen once... compression jam and it jumped the shim and jammed itself behind the tappet fin. not sure exactly how it flipped, I'm thinking it wedged itself deeper than what you have it. but it looks almost exactly the same.

Did you ever find the cause of the problem?

[lurkingknight]

not specifically, I can't tell you exactly how it ended up like that, just that it did.

The compression jam was the problem that started the whole chain of events but I'm not entirely sure how the tappet skipped. With the gearbox opened I could see that the fin may have caught on a shim and twisted to get around the tappet post on the gear, I would guess that the sector was not shimmed enough leaving a larger gap on top of the tappet post that the tappet manage to slip itself into when I forced another cycle (or two... or three) after the compression jam.

Usually the first shot will fart with the jam, second if your gears are going fast enough will either strip your piston, or if you have steel teeth, bump/skip across the rack, or if you really force the issue, will catch mid cycle and jam the piston back all the way. Things tend to go the path of least resistance so there could have been enough of a gap to force its way in there.

That particular gun didn't have a sector clip on the tappet post, where a sector clip might widen that a tiny bit and prevent it from jamming under the tappet fin (in addiction to delay tappet going forward to help feed higher rate of fire) . My other 2 guns have sector clips while the one I had the problem on didn't

I reshimmed the sector a tiny bit tighter and higher and fixed the the jamming issue so it hasn't reoccurred. That's really all I got on it.

[Latvian291]

Originally Posted by lurkingknight

not specifically, I can't tell you exactly how it ended up like that, just that it did.

The compression jam was the problem that started the whole chain of events but I'm not entirely sure how the tappet skipped. With the gearbox opened I could see that the fin may have caught on a shim and twisted to get around the tappet post on the gear, I would guess that the sector was not shimmed enough leaving a larger gap on top of the tappet post that the tappet manage to slip itself into when I forced another cycle (or two... or three) after the compression jam.

Usually the first shot will fart with the jam, second if your gears are going fast enough will either strip your piston, or if you have steel teeth, bump/skip across the rack, or if you really force the issue, will catch mid cycle and jam the piston back all the way. Things tend to go the path of least resistance so there could have been enough of a gap to force its way in there.

That particular gun didn't have a sector clip on the tappet post, where a sector clip might widen that a tiny bit and prevent it from jamming under the tappet fin (in addiction to delay tappet going forward to help feed higher rate of fire) . My other 2 guns have sector clips while the one I had the problem on didn't

I reshimmed the sector a tiny bit tighter and higher and fixed the the jamming issue so it hasn't reoccurred. That's really all I got on it.

Might the tightness of the grip screw affect the jamming of the gearbox? I always thought the grip should be as tight as possible without breaking anything.

[lurkingknight]

probably not.

[Latvian291]

I am stumped. The only thing I can think of at this point is the motor isn't strong enough to pull the spring back and flipping the anti-reversal latch to take down the gearbox is what caused the broken tappets.

[Latvian291]

Problem considered solved. In my opinion the problems were both caused by improperly adjusted motor depth screws. Adjusted my AIMS and it works great now. I broke the piston in the 74 so I will have to replace it first before pronouncing that the problem, although I am sure it is.