CYMA P90 full upgrade - Finished... For now...

[Davegolf]

They are also one of the quietest AEGs going, especially with a well built gearbox.

I remember running up the escalators at The Mall with the P90 one handed, epic gun and it's not an M4

Extended butt pad is good

 

[Asomodai]

ProWin Hop unit, TM AUG HC Barrel and Prommy purple Bucking and nub installed. Had a lot of issues getting the arm to engage and the rubber to sit correctly but all good! Man the old Hop unit is terrible!

Also put the M4 Flash Hider on it ?

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[Skara]

How did it turn out?

Quite interested since I heard they can be silenced to pretty stupid levels..

 

[Asomodai]

How did it turn out?

Quite interested since I heard they can be silenced to pretty stupid levels..

Getting started next weekend. Work finishes for Christmas on Friday where i'll have a week and a half to go for it! 

The EG1000 has been replaced with an SLD High Torque as I wasn't sure the TM would have pulled the gears. I may also switch out the 14:1 set for a 13:1 set. 

 

[Asomodai]

So some work has been done!

Got out the guarder compression set, lubed up the O-rings with silicon. Seems to have a very good air seal. 

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Unfortunately the King Arms Tappet Plate is too thick where the Nozzle should rest, this goes for the Guarder nozzle and the SHS metal one. 

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I was going to stop there, but got worried that the original Tappet Plate wouldn't be compatible with my nozzles either, so decided to take the gearbox apart. Seems pretty solid to me, came out really easily as well. Wiring whilst poor quality wire, is well soldered. 

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Motor cage comes off easily. 

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Trying to get the top plate off I managed to gouge a deep cut into the side of my thumb. Bled profusely. I did the same sort of thing when I took a G36 gearbox apart.

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Despite my best efforts, the gearbox fell apart when splitting. At least the spring stayed in place! Gears seem solid with a large nub to activate the tappet, spring guide is surprisingly made out of metal and with a bearing. Usual crap compression gear, though seems to have a fair air seal. Crap clear Air nozzle that is roughly cut. 

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Uh-oh, one of the bushings seems to have broken at some point. All the bearings fell out of the gearbox easily with ease. 

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My new Guarder bearings, look much better quality. The large bearings are just as loose in the gearbox as the standard ones, though the round ones fit in tight. 

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Cleaned up gearbox with guarder cylinder and piston set, M90 spring, V6 specific Ultimate spring guide, Specna arms 14:1 gears and Guarder bushings. The only thing that's stock is the tappet plate (Luckily the SHS nozzle fits fine, slightly loose but good enough) and anti-reversal latch. 

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I am a bit worried about the nub on the top gear being smaller then on the original gear set, this might result in pre-engagement, what say you? Shall I get a delayer chip just in case? Next is to shim the gears (No idea what I am doing with that!) and put it back together again. 

 

[Prisce]

Proper engineers plaster there ??

 

[Asomodai]

Got a Delayer chip. Had to file it down with the Dremel a bit to fit onto the spindle.

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I put the gearbox together, unfortunately the piston would rack all the way back and get stuck on the last tooth. Any ideas why this might be? The piston cant go back any further as it has hit the spring guide bearing. 

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[Asomodai]

It lives! 

Had to tear out the ball bearing on the piston head as there was not enough space for the piston to come back all the way.

Does the gearbox sound ok from the video? I haven't really lubed much at all, just the cylinder set. The Air Nozzle and piston finishes firing in random positions, is that normal? It is currently running on a 8.4 Nimh and a weak motor so might sound off. Getting replaced with a 7.4V lipo on deans and a SLD 22TPA Neo motor.

 

[Asomodai]

Took it apart again, used lithium grease on the gears and piston teeth and silicon grease on the piston sides, head, air nozzle and spring guide ball bearing. Put her all back together and all seems fairly good. Air nozzle and piston don’t seem to want to regularly return to the same position. But that could be normal? No idea!

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[Immortal]

Interesting project. Looking forward to seeing it finished. 

Alas I don't have any answers to your questions.

 

[Battle_Buddy]

Looks all very complicated 

can’t they just make these good out of the box? I don’t buy my Sony TV and immediately start taking it apart. 

 

[Prisce]

How many teeth does that piston have? And your sector gear?

Have you sorted your AoE?

Gearbox doesn’t sound terrible, but that air nozzle has me wondering. 

Looking back at the video of mine out of the shell it finished very similar each time.

 

[Asomodai]

How many teeth does that piston have? And your sector gear?

Have you sorted your AoE?

Gearbox doesn’t sound terrible, but that air nozzle has me wondering. 

Looking back at the video of mine out of the shell it finished very similar each time.

15 tooth piston, 16 tooth sector gear

Aoe is fine. I adjusted the motor height last night and it does sound a bit better.

 

[Prisce]

Hmm, think you may get a couple of feeding issues with the way that nozzle is going. 

If you place  your finger over the nozzle does it hold pressure or all leak out?

I think some of your parts may not be compatible. 

Not too familiar with the P90 box, but thinking about the V2 box I built I wonder if your tappet plate is catching somewhere. That or some of the parts may be slightly too tight on tolerances. 

Just checked mine again and it finishes the same place every time.

 

[Asomodai]

Hmm, think you may get a couple of feeding issues with the way that nozzle is going. 

If you place  your finger over the nozzle does it hold pressure or all leak out?

I think some of your parts may not be compatible. 

Not too familiar with the P90 box, but thinking about the V2 box I built I wonder if your tappet plate is catching somewhere. That or some of the parts may be slightly too tight on tolerances. 

Just checked mine again and it finishes the same place every time.

The compression is pretty much close to perfect. 

I just put it together and tested FPS. On an M90 it is doing around 315 FPS with 5 FPS variance with the hop off. Despite the nozzle ending up in a random place every shot, it appears to be feeding well with no missed shots. 

On a 8.4v NiMH battery and terrible CYMA stock ferrite motor its running at about 17rps

 

[Skara]

The compression is pretty much close to perfect. 

I just put it together and tested FPS. On an M90 it is doing around 315 FPS with 5 FPS variance with the hop off. Despite the nozzle ending up in a random place every shot, it appears to be feeding well with no missed shots. 

On a 8.4v NiMH battery and terrible CYMA stock ferrite motor its running at about 17rps

You'd need a fcu of some sort to make every cycle regular. I have no idea if there's such thing for p90s.

 

[Asomodai]

You'd need a fcu of some sort to make every cycle regular. I have no idea if there's such thing for p90s.

Does it matter if I don't have one? It appears to feed fine despite the nozzle being completely in the forward position before pulling the trigger. Its the first I have heard of this problem and other people don't have a FCU with a similar spec and don't appear to have a problem.

Maybe I need to swiss cheese the piston and put in a heavier spring. 

 

[Skara]

To be honest, it doesn't.

Airsoft guns have been working for 30+ years without them, and they will for another 30+

In the long run you may have troubles with the motor though, as it requires a lot more strength to pull the last mm of the spring, compared to pulling it from a more relaxed position.

This from a discussion I had earlier this morning with a teammate about pre cocking.

Swiss cheesing and heavy springs don't fix the "issue", as the anti reversal latch will always stop the gears in whatever position they are when the current is cut off.

I personally find this annoying as hell, but most likely it's because I'm too used to electronic triggers to even consider having a gun without one. They just make everything run so smooth compared to standard, all mechanical gearboxes..

 

[Asomodai]

To be honest, it doesn't.

Airsoft guns have been working for 30+ years without them, and they will for another 30+

In the long run you may have troubles with the motor though, as it requires a lot more strength to pull the last mm of the spring, compared to pulling it from a more relaxed position.

This from a discussion I had earlier this morning with a teammate about pre cocking.

Swiss cheesing and heavy springs don't fix the "issue", as the anti reversal latch will always stop the gears in whatever position they are when the current is cut off.

I personally find this annoying as hell, but most likely it's because I'm too used to electronic triggers to even consider having a gun without one. They just make everything run so smooth compared to standard, all mechanical gearboxes..

So considering I am getting a 22TPA SLD High Torque motor for Christmas. Maybe that will solve the issues? Its a stronger magnet so in theory there is less play in the pinion. Or am I still not following? I just installed an M100, Motor is really struggling now, though it seems as the nozzle is ending up in less random positions (though still random). 

 

[Prisce]

The compression is pretty much close to perfect. 

I just put it together and tested FPS. On an M90 it is doing around 315 FPS with 5 FPS variance with the hop off. Despite the nozzle ending up in a random place every shot, it appears to be feeding well with no missed shots. 

On a 8.4v NiMH battery and terrible CYMA stock ferrite motor its running at about 17rps

Maybe it’s a quirk of a P90 box??‍