Just finished work on my own CYMA M14 (DMR)
Taking it apart is like any other gun - easier after you do it a couple times
The gearbox can definitely be a little finnicky. It has a few small springs, and free-floating parts, with little bits that will definitely want to ping off and be lost forever
Main bits I did;
- ZCI High Torque motor
- m140 spring
- Short stroke by 2 (knocked 40fps off each tooth)
- Flat hop nub
- Steel bearing spring guide (stock one is plastic)
- Perun AB++ Mosfet
- New piston/head (previous one had a bit of wear on the runner)
- Degrease/regrease, general cleaning of hop/rubber/barrel
- Shimming is tricky with m14 (see Negative's vid), it is a noisy gun, you can quieten down a little, but, it's a loud boi
I kept the shimming basic on the spur and sector, .1mm each side, and shimmed the bevel up .5mm total (.1mm on top), which gave me a happier sounding motor
It's likely possible to shim the other gears further to reduce up-n-down more, but I know the GB can be fussy, so didn't feel need to chance it
Some notes;
- Take it steady on disassemble (as you generally should)
- Hop rubber is the shortened type, like snipers, so either buy to suit or cut one down if you're confident
- The window to the gearbox is about half the opening to what you'd usually expect, so can be hard to get fingers through to hold cylinder down -- if you need to stick a stronger spring in there
I used a magnet (taken from an old speaker) and a screwdriver in the spring guide to help hold in the spring so I could put the case on
- CYMA is a TM clone, so is compatible with TM replacements/parts
- the G&G M14 is it's own thing, steer away from parts for your CYMA
Any questions/issues, feel free to shoot me a DM