Help spenca gun won't fire guessing piston gone

[Jedidazzy1990]

Hi all my gun won't fire but making a grinding noise checked the motor is sound and gears I'm guessing the piston has gone as I found a bit of one of the teeth while taking apart 😞😞 specna arms g series 

[Rogerborg]

Sorry to hear that. Have you got the whole gearbox apart?  If you have, damage to the rack should be pretty obvious.  If it is the piston, well, that's where you want the failure to happen - they're essentially consumable parts.

 

When it goes back together, get it shimmed and lubed, and it would be worth checking the angle of engagement to see if it's way out.

 

Also, if you were running it on 11.1V, I'd suggest going down to 7.4V since you now have reason to suspect that it's not as happy as it could be.

[DerDer]

If you have it still disassembled, would do a thorough inspection for remnants of the piston. Bits of chewed up piston can make their way into the teeth of gears and various parts of the gearbox.