Misfiring HELP!

[robbiec97]

Hi all,

 

So I recently purchased a Specna Arms SA-F01 Flex and decided to upgrade some parts..

 

SA 13:1 Steel Gears

SA High Torque Motor

SA CNC Aluminium Rotary Hop-Up

SA 6.02mm Steel Inner Barrel

Gate Pico SSR3 Mosfet

Nuprol 11.1v 1300mah 25C Li-Po Battery

SA M100 Spring

Now I’m getting firing issues in semi-auto only, mainly dry firing, sometimes double shot, full auto works flawlessly.

 

Ive stripped down and rebuilt the entire thing 4 times now, and I cannot for the life of me figure out what’s wrong, motor height, gear shimming, AOE are all perfect, can’t see any damage anywhere, would over spin cause this issue?

 

Any help would be greatly appreciated!!

[Leo Greer]

That hop unit is not an upgrade. Try the original one and see if that fixes it.

[robbiec97]

Tried the original hop-up, no difference at all😬

[Leo Greer]

That’s worrying.

 

What I would do next is remove the upper and track nozzle position while dry firing—if it doesn’t fully extend due to sticking, tappet PME, etc, that’s your issue.

 

You can also try manually pushing the nozzle in and it to just the level of friction it has with the nozzle tube, and the friction of the tappet plate on the gearbox.

[Rogerborg]

The double shot on semi is typical of beefing up the motor and going to 11.1V, and the gears won't be helping either.  It's not that anything is wrong, it's just too much right. Some folk get lucky on 11.V, but I've had double-shooting on every M100-ish gun I've tried it with.  7.4V, or a mosfet with active brake will sort it.  You could try adding more factors, like a stronger spring + short stroking or even a wide-bore or shorter inner barrel, but the inherent issue is that the pixies in there are too angry now.

 

The mis-feeding may just be mid-cap syndrome (too much spring pressure misaligning the nozzle when full, or not enough for the BBs to feed quickly enough when nearly empty), or Specnas being Specnas. Some of them are super-fussy about mags, even by airsoft "standards", as griped about here a few times.  And you can't even rely on "Specna" mags feeding in "Specnas" given the variety of OEMs that they seem to use for their ever expanding range.

 

tl;dr version, you might have to use hi-caps and/or shim the front or rear of the mags to get them feeding reliably.  That's just airsoft reality.