Piston jamming Issues with Titan TM HK416D NGRS need some advice.

[uncleanlatent]

Starting this thread as I've run out of ideas and need some outside perspective on some of the issues I've been having with my AEG. 

The piston locks back, almost like a pre-cock, and causes the motor to run but not turnover the gearbox. This results in a god almighty screeching sound. 

I brought the RIF second had from a guy who had it upgraded by Daves custom Airsoft. When I got it the first thing I did was to disassembled it, and gave It a good clean and re-lube. It ran fine for 4 games before these problems started. I contacted the guy and he said he never had any issues....go figure. 

 

I sent it back off to DCA last month for them to diagnose the problem and fix it. After great expense they sent it back after replacing the motor, re-wiring the mosfet and a few other maintenance tasks. Once again the gun worked fine for 3 games before the same problems started again. 

In frustration I sent it back to DCA for them to take another look at it. 

 

In retrospect I shouldn't have sent it off....but hey ho. 

 

Any ideas or pointers would be helpful and I'll try to answer as much as I can. I've spent well over 1k on this thing and don't want to relegate it to the bone yard. 

 

My mate said it could be the batteries I'm using in it? I'm using Titan 3000mAh 7.4v Nunchucks with a deans conversion. He said the low current of these could not be providing the motor enough torque to turn over the gearbox completely causing this jam. 

 

Cheers guys.  

 

[Adolf Hamster]

Screeching noise sounds more like a mechanical issue than a stalled motor.

 

I'm tempted to think the motor height adjustment is backing out gradually when firing until eventually it's enough to slip on the bevel.

[Colin Allen]

I had very similar symptoms with a RIF and it was exactly as Adolf states.

Over time, the motor height adjustment screw backed off; when the piston was almost the whole way back, the resistance in the gearset was such that the pinion slipped on the bevel.

A tiny drop of thread lock on the adjustment screw solved the problem.

[gavinkempsell]

Just now, Colin Allen said:

A tiny drop of thread lock on the adjustment screw solved the problem.

Exactly what I was planning on an L85 carbine that unscrewed itself at my last game day.