Cyma Aks-74u build list help

[Titchiemagoo]

Hiya everyone and thankyou for reading. I'm hoping someone could help please.

I have got a (CM.045A) Aks-74u vfc clone so a v3 gearbox,  I was told it had low compression when I bought it so upon testing it shoots a little limp and even on a 11.1 it  feels like something is binding up on the inside.

So I thought I'd replace the internals while I'm on so I'm looking for a list of upgrade parts that people has used and know work.

I'm looking ideally for faster firing and more range on a 11.1 as this is gonna be my main gun instead of my ak47 which I'll probably sell to fund the upgrades.

Or will build up the upgrades over time as money is tight.

Also the main thing is which mosfet do I go for, which midrange brand/model is the best in this circumstance. 

Any help is welcome and very gratefully recieved.

[Colin Allen]

Perun V3 Hybrid
SHS 16:1 gears
SHS Delayer chip
Maple Leaf Macaron yellow plus red nub (from AK2M4) 
XT inner barrel
XT cylinder head
XT POM piston head
XT pink 14 tooth piston
A decent brushless motor or an SHS high torque if cash is in short supply.

Edited June 19 by Colin Allen

[Adolf Hamster]

10 hours ago, Colin Allen said:

Perun V3 Hybrid
SHS 16:1 gears
SHS Delayer chip
Maple Leaf Macaron yellow plus red nub (from AK2M4) 
XT inner barrel
XT cylinder head
XT POM piston head
XT pink 14 tooth piston
A decent brushless motor or an SHS high torque if cash is in short supply.

 

For 11.1 thats probably a sound ratio.

 

I would say the non-maple leaf nubs can sometimes be a bit off-square, so i'd typically go for the maple leaf branded one.

 

If cash is shorter then an external mosfet like an ab++ or warfet could be substituted.

[Colin Allen]

3 hours ago, Adolf Hamster said:

 

For 11.1 thats probably a sound ratio.

 

I would say the non-maple leaf nubs can sometimes be a bit off-square, so i'd typically go for the maple leaf branded one.

 

If cash is shorter then an external mosfet like an ab++ or warfet could be substituted.

An AB++ would be a decent somewhat cheaper alternative.

[Skara]

If going 16:1 or 12:1 I would suggest to use helical gears.

The reason is that 16/12 spurs have a weird tooth profile that tends to wear bevel gears much faster than 18/13 ratio gears, while helicals have dedicated bevel/spur gears for those particular ratios.

 

My Cyma Ak runs on:

• BOB (box o' bits) 13:1 gearset, short stroked by 4 on release;
• FPS high speed delayer;
• FPS tappet plate, modified to set the timing;
• Solink 35k Advanced Brushless motor (unibearing, so no arl needed);
• Unmarked spring, probably a M100/M110 to stay below 1J;
• Perun V3 Hybrid + Clicker;
• Lonex gearbox shell + motor cage;
• FPS 8mm solid bushings;
• FPS piston body, metal rack;
• FPS POM piston head;
• FPS alu cylinder head (I generally prefer plastic cylinder heads, this is just for testing);
• FPS cylinder (3/4 hole);
• FPS 19.70 POM nozzle;
• Begadi Nebo hop unit;
• Maple Leaf Super Macaron 70°;
• Prometheus 247x6.05 barrel;

 

This setup gives me 24/25ish RPS on a 7,4v and just about 35/36 on 11.1, very snappy and somewhat "quiet".

p.s. my barrel is shorter than the stock, I have removed the typical aksu flash hider and adapter. Stock barrel length is roughly 290/300mm iirc.

 

Keep in mind that these lists are a rough guideline, the wonderful world of airsoft tolerances may result in your parts not fitting together like mine or someone else's did.

[Titchiemagoo]

On 20/06/2025 at 11:06, Colin Allen said:

An AB++ would be a decent somewhat cheaper alternative.

Are they the ones that just go in between the lipo and rif lipo plug but you can also hardwire in.

[Titchiemagoo]

On 19/06/2025 at 20:55, Colin Allen said:

Perun V3 Hybrid
SHS 16:1 gears
SHS Delayer chip
Maple Leaf Macaron yellow plus red nub (from AK2M4) 
XT inner barrel
XT cylinder head
XT POM piston head
XT pink 14 tooth piston
A decent brushless motor or an SHS high torque if cash is in short supply.

Hiya, thanks for the reply. What would be the difference between 13:1 to 16:1. Like how it would perform. 

What I'm working with.

[Colin Allen]

11 hours ago, Titchiemagoo said:

Are they the ones that just go in between the lipo and rif lipo plug but you can also hardwire in.

It has to be hardwired, but that is quite easy as you do not need to open a V3 gearbox to do so.  However, it seems that you are going to open the gearbox anyway.

4 hours ago, Titchiemagoo said:

Hiya, thanks for the reply. What would be the difference between 13:1 to 16:1. Like how it would perform. 

What I'm working with.

It would run faster on 13:1, giving you a higher rate of fire and a marginal improvement in trigger response.

 

However, if using it on an 11.1v with 13:1 gears, you might be heading for premature engagement (PME), where the piston cannot go forward fast enough and is engaged by the sector gear as it is moving forward.  That gets messy.

Edited 14 hours ago by Colin Allen

[Titchiemagoo]

1 hour ago, Colin Allen said:

It has to be hardwired, but that is quite easy as you do not need to open a V3 gearbox to do so.  However, it seems that you are going to open the gearbox anyway.

It would run faster on 13:1, giving you a higher rate of fire and a marginal improvement in trigger response.

 

However, if using it on an 11.1v with 13:1 gears, you might be heading for premature engagement (PME), where the piston cannot go forward fast enough and is engaged by the sector gear as it is moving forward.  That gets messy.

Thanks for replying, I can solder fairly well, I used to mess around with r/c cars and changing connectors on lipos or rifs if there tamiya connectors etc. So I'm confident with that I think. So you think 16:1 is the best bet. Just wanted to be sure, thankyou ever so much for your help your a 🌟