Airsoft Forums UK

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now to rebuild

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that's some greasy shit ?

was gunkrd up to hell man

Yuck!  Those slotted bushings as well!

cyma what ya expect lol

8mm cross bushings in 516

are "slightly" different to 621

(and "revised" blue plastic 5xx series)

The idea is that you fill the X up with grease

and in use, it warms & cascades onto gear axles

(of course a smear onto gears/teeth/axles anyway)

I presume you got a spare new o-ring

& perhaps 7 wraps of ptfe on loose white cylinder head

however with improved seals the gun might be a bit hot

as the std Cyma piston o-ring is a little meeehhhhh

and the white/blue cylinder head is still loose as fuck

and you have a clear tappet plate (hard & brittle)

compared to better blue polymer tappet

(still bespoke tappet with cut outs & SHS red nozzle is a

loose wobbly fit on tappet - so kinda stuck with Cyma nozzle)

Now you could improve seals (o-ring/ptfe)

but you may be firing over 350fps once sorted

if you are shooting say 390fps

them see if you have a M3 bolt & hopefully nylon lock nut

then remove alloy spacer in piston which reduces spring tension

which in turn should see fps go down about 45rps

& rof increase about 2 rounds per second

(might be a smidge more but reckon 2rps aprox)

Shimming on Cyma's is not THAT bad

so hope you kept the old shims & noted them

There "might" be a bit extra play in gears

BUT don't go nutz trying to eliminate it completely

as shimming too close/tight is a common mistake

at best you might only be adding say 0.1mm  to each gear

DO NOT WORRY ABOUT BEVEL - likely leave it as it was

it should be say 0.3mm on top of bevel

and leave it underneath bevel

(pinion in place will prevent it sliding over anyway)

the spur will likely have say 0.2mm below it

and what ever is needed to take up slack on top

sector will have a whisker more below - say 0.25mm

and whatever needed on top (likely around 0.25mm

again, so sector is roughly centred in box)

spin test blah x 3 so it rolls nicely

(if bushings are dry add drop oil on axles

to lessen squeaky dry bushing/axles shrill on spin test

bushings loaded with grease don't spin well when testing)

lay box so selector plate is facing up

lift sector up and watch spur's axle

if spur's axle moves when lifting sector's slight play

then they are shimmed a little too closely

with extra play in those 2 gears

basically the slapped together shimming at sweat shop

isn't THAT far out (honest)

so keep bevel as it was

and if excess play on other two gears

then look to take up some of slack perhaps

try not to use massive outer diameter shims

on top of sector

(very large diameter shims can run a tiny

tiny slight risk of catching on tappet fin)

& below bevel

(very large shims can impede the bevel to spur

meshing of teeth as they meet/mesh in use)

anywhere else use whatever shims work

(just those two points very big diameter shims

should be avoided if possible, if you have OCD)

if you bought SHS shims then the hex shims are 0.1mm

and the silver / copper ones should be about 0.2 & 0.3

(something like that, but hex = 0.1mm there abouts)

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is that with new seals or as it was ???

coz if you improved the meeehhh seals

I'd be quite suprised if it still shoots at old fps

and the Cyma seals are not great tbh

the head is still loose & compression quite poor

 only had to add one shim to it bud

yeah shes firing just under the limit now

didnt on the 516 actualy managed to get a gd air seal on the standard seal

was generaly just opening her up give her a clean and see what was causing the noise

That's alright then...

I'll assume that whoever downgraded the spring

from std 390fps China spec for US market

checked the seals at same time when changed spring

13rps is pretty decent - is that with deans yet ???

nah that wasnt the actual fire rate bud that was just how many single shots i took rps has went up .4 lol not yet ordering deans on tuesday

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