Cyma Cm.621 Upgrades

[Misery]

hahhaa all gd bro

oh deffo man cant wait to get out with now have a feed issue but did change hop rubber so will revert back to stock for now

 

[Adolf Hamster]

that fecking trigger buggered me up so many times lol

v3 triggers, that's all i'm gonna say......

 

[Misery]

lol havent seen em

 

[Adolf Hamster]

lol havent seen em

twice the fun, literally.....

 

[Misery]

well that was a shit show still double feeding  so have stripped back down and found that the bushs have moved aswell so gonna order new bushings cause these literaly just fall out of the gearbox side,so more waiting around woooohooo lol

 

[Sitting Duck]

WAIT WAIT WAIT a second...

Double feeding so order new bushings ???

First things first - gearbox = pisspot zinc alloy

bushings = steel (sorta)

which material do you think has worn loose ???

(I suspect new bushings may still be a little loose

plus different bushings/bearings will throw shimming out

and all of this is likely to be unrelated to feed issues really)

Poundland - £1 purchase of 2-part expoxy

glue bushings in by a LIGHT smear around edges of box - refit & allow to set

Double feed or misfeeding ???

without going into detail too much...

assuming bb's slip through bucking/hop unit into barrel etc...

(and tappet/nozzle is cycling correctly to feed/chamber bb etc...)

is the mag a little loose in gun ???

can you put a bit of cloth (some use velcro - felt part of it, tape)

place a bit of cloth/tape at BACK of magwell, effectively between  gearbox & mag in well

this will very slightly shift the hop forward as the mag is inserted

(very very slightly shifting the mag/hop forward from box which will create a whisper more room

in doing so there will be a slight increase in available room in front of nozzle that should assist in feeding

there is a slight chance that fps "might" lessen slightly but test if it helps with feed issue first)

Realistically - wind the hop off, see if gun feeds 101%

if it feeds OK with hop off then things look OK

what "might" be happening is bucking is greasey so not applying grippy pressure to backspin/lift bb

so you wind on more pressure and create jams etc... (often diagnosed as misfeeds - nope it's a jam)

is the hop working ???

you don't need to see nub forming a solar eclipse as you look down hop/barrel

it just needs a very slight bump to create backspin

the barrel is 6.03~6.05mm with a 5.95mm bb, you can't have it looking like a stopcock/valve half open

tilt gun on its side 90 degrees & fire to see bb's curving right/left = hop sorta working

but if you keep winding it on you'll get a jam in the end

The v2 gearbox is cunt for nozzle/tappet tolerances

the tappet fin could be worn - but I kinda doubt it

(plus the cyma tappet is a bespoke bastid)

is the box properly all bolted back into place, with box in position

(be careful tightening the stock tube up really tight, especially in metal receivers - yeah its plastic)

but if stuff is slightly out of whack, nozzle can rub on hop impeding its operating (feed/chamber issues)

as said previously - try shit in other gun

test other mags - use good bb's, swap out barrel/hop combo first

basically try a process of elimination/trial n error before steaming in & buying new bushings

(which still might be a bit loose if cheap box allows present bushings to fall out)

the tape velcro thingy might assist if shifting the hop forward very slightly

and allow a smidge more room/clearance for bb to slip past the nozzle at full retraction

the cyma sector will not allow you to fit a normal delayer, so that suggestion is not really an option

stuff like

filing down the nozzle is NOT ADVISED as you will likely lose fps from shortening nozzle

(the velcro/tape at back of magwell will slightly do the same effect but without fucking shit

as you can always remove velcro/cloth tape - but can't put back material you filed off nozzle)

it is too easy to steam in and think it must be this - often it isn't

and doubt if bushings will resolve the issue - well not as I can see

in your pic, the sector cam was just behind the tappet fin

so it needs to be slightly in front of fin when reassembling

or box won't close

also - might worth rotating tappet spring 180 so the loop is closer to tappet underside/hook

than at the bottom like in your pic - but depends on tappet spring as some have "loops"

formed differently than others. Some say it don't matter which way it is fitted

but on reg trolley switches the loop on the "hook" goes close to tappet underside

to keep the tappet spring closer to tappet in operation etc...

(probably won't make a difference but wondering if spring was fitted that way round)

close of Cyma from TWG...View attachment 68008

looks like your tappet spring might have been fitted the other way around

(might make next to no difference, but the loop is tighter to tappet underside (usually)

than leaning towards bottom of hook)

Most of this is my OCD kicking in - I'd try say the tape in magwell first

before ripping box open, swapping tappet spring around and removing stuff to glue bushings etc...

if box was assembled OK then it "should" just work

looks std with no massive amount of wear anywhere

so it "should" work, not as if fucked components or new nozzle too long fitted

so again "should" just work as intended without going nutz

some guns/mags like the tape in magwell to reduce wobble and help feeding

it is another kinda bodge/workaround on M4 style guns/mags with sprung/floaty hop units

but providing other hop/bucking/feed/jam issues aren't involved

(hence swap/try the other hop/barrel combo in there from other gun too)

don't go stripping down a hop/barrel combo that works OK - just the complete unit try out

to diagnose what the main issue might be why the sod don't wanna feed too good

ps - be carefull with the two black wires getting close to that little hole

that is the where that little pin goes through and if wires are not routed carefully

it is easy to nick/puncture them with the receiver pin - I've done it

(so you learn by our mistakes certain things to take note of next time & stuff to watch out for)

yup - people think v2's are pretty straight forward - well they are but there are a few things to note

and stuff like routing of wires - well basically everything I guess needs a little attention to detail

you probably was OK, but just looked a tiny bit close to the pin hole

and like I said I've punctured them wire(s) in the past not checking/routing stuff carefully

pps - shims on sector gear go in front of tappet not underneath

but sure you refiited it all correctly - with shims on top of sector gear & tappet fin

 

[Misery]

no wasnt meaning the bushings are causing the problem of the double feeding the bushings coming loose i oticed because of the fire selector switch didnt feel right was stiffer than it should of been thats when i noticed the bushings a couple of the bushings had moved out of there holes whrn took apart they werent as tight in,but if u recomend to 2part epoxy em in then thats fine i thought i would of had to replace them

that spring i will refit the right way when i refit

dont get me wrong she was firing bud no unusual sounds just the odd double feed which i put down to the hop rubber upgrade so reverted bk to stock at same time as checking why the switch was tight which i assume is cause the gear has shifted ever so slight and put pressure against the casing and against the lower receiver causing it to be stiff

as for the wiring yeah ive noticed that im actualy contemplating replacing the wire as few bits are looking a bit dodgy and i have the time to sort it properly than just leave it till it goes lol

thank you for telling me that with the shim that is noted for when i refit everything will get epoxy ordered in tonight so i can get it done tomoz or sunday thank you again i know i must eb a pain in the ass lol

 

[Sitting Duck]

shove a bit of grease/oil in the rails of blue selector plate

so that it glides back n forth smoothly

not tons of it but a bit here n there

these boxes are slapped together by 5 year olds bone dry

no smoothing of burrs n shit, rough cast edges etc...

so things like selector plates n stuff glide like a frozen wobbly shopping cart

going over speed bumps in a gravel track - pretty fucking shit

slapped together by kids doing piece work: get it in & whack it out sorta stuff for 50 cents

(that'll be alright, in will run/wear itself in)

no wonder we end up doing the finer finishing ourselves at times

The 8mm bushings shouldn't foul the selector plate as such

bushings tend to be a bit thicker inside than outside

bearings though, can protrude a bit more and sometimes snag on selector plate

just a tiny drop/smear of oil/grease should see plate glide smoothly

then the selector switch should operate better without snagging/strain

(be careful of oil/grease going into the electrical mosfet/sensor switch behind selector plate)

no need to dismantle shit, just a smear worked into runners, glide back n forth

& it should work itself in no problem

these cheap guns are hardly finished at all

and cheap Cyma cm.028a - jeez them gearboxes have razor sharp edges

(could feel my fingers getting shaved & sliced on one of those fuckers)

so often these high precision bit of engineering (sarcasm)

need the odd bit of smoothing & a bit of grease as the blue Smurf jizz

was just splurged in there at random it seems on them gears/bushings

try the tape in magwell - might help/assist with some feed issues

sometimes people put tape either side of magwell's long edge to reduce mag wobble

other times certain mags, some midcaps can be a bitch to feed and others have felt taped the back

shoving mag/hop forward to assist feeding or nozzle clearance

(and it don't work you can remove it - no biggy)

 

[Adolf Hamster]

See this is how it begins.....

It'll be 13:1 short stroked before it ever hits the field

It can be a rewarding thing getting a gun running sweet especially if you do it with care and attention rather than filling it with expensive bits.

The trick with the maple leaf hop rubbers is they seem to have marginally longer feedlips than most brands, great for air seal (and therefore accuracy) but can make it hard for the mag to shove a bb past it.

Way to check is to look up the feed tube when the barrel is installed see if there's too much poking out, a little is ok but more than about 0.5mm and it might be causing issues (although normally that's occasional double feeds in a sea of blanks)

Generally i keep a pdi w-hop handy as my go-to for guns that dont like ml stuff.

 

[Sitting Duck]

See this is how it begins.....

It'll be 13:1 short stroked before it ever hits the field

It can be a rewarding thing getting a gun running sweet especially if you do it with care and attention rather than filling it with expensive bits.

The trick with the maple leaf hop rubbers is they seem to have marginally longer feedlips than most brands, great for air seal (and therefore accuracy) but can make it hard for the mag to shove a bb past it.

Way to check is to look up the feed tube when the barrel is installed see if there's too much poking out, a little is ok but more than about 0.5mm and it might be causing issues (although normally that's occasional double feeds in a sea of blanks)

Generally i keep a pdi w-hop handy as my go-to for guns that dont like ml stuff.

good points there

fuck me - prommy buckings are quite bad too

must be the Leslie Ash of bucking lips...

think there is lesson here that applies to airsoft too

just don't go too fucking nutz get some work/upgrades done

 

[Davegolf]

What is wrong with people, why can’t they age gracefully!?

I always wonder what happens to the Botox/silicone when you get buried or cremated lol, must play havoc with the burners ?

 

[RonLancs]

What is wrong with people, why can’t they age gracefully!?

I always wonder what happens to the Botox/silicone when you get buried or cremated lol, must play havoc with the burners ?

Ohh the smell

 

[Sitting Duck]

Not to mention fake jugs

I mean when Lola Ferrari croaked

that must been a cremation/coffin to remember

(let alone lift)

still a struggle to shut the lid I expect

 

[RonLancs]

Not to mention fake jugs

I mean when Lola Ferrari croaked

that must been a cremation/coffin to remember

(let alone lift)

Imagine mid service, POP.. POP.. 

The OP's there like yeee so anyway my gearbox xD

 

[Cannonfodder]

What is wrong with people, why can’t they age gracefully!?

I always wonder what happens to the Botox/silicone when you get buried or cremated lol, must play havoc with the burners ?

The joys of Google 

Edit: Botox is organic so I think it'd decompose with the body after burial or burn up in the cremation 

 

[Adolf Hamster]

y'know i always did wonder why when you're going to all the expense, the pain, the effort of plastic surgery would you not at least choose to have the result look good?

remember seeing the story about some korean pop star who started off pretty good looking, went deep down the plastic surgery rabbithole thinking her looks were what made her popular (and refusing to accept the end of her 5 minutes of fame), ran out of money and injected cooking oil into her own face in desperation which backfired bad. and it finished with her wanting plastic surgery to get back to looking how she looked to begin with.

of course there's a paralell here- people who start off with a perfectly nice ak and put an m4 stock on it thinking it'll make it look good

 

[alxndrhll]

of course there's a paralell here- people who start off with a perfectly nice ak and put an m4 stock on it thinking knowing it'll make it look good

FTFY ?

 

[Shamal]

34 minutes ago, Cannonfodder said:

The joys of Google 

She is weird! 

 

[Misery]

haha this shit has made my morning espicialy bout lola's casket haha

 

[Davegolf]

She is weird! 

Surely that just comes with being a mortician!?