Cyma with no power no matter what i do with it

Soo… Long story short, got husband of the chef that i work with and her kids hooked on gel blastery, and even thou i told them to run it by me first, he bought a second hand cyma jd-002 long from a mate that was build by a shop after the stock nylon gears stripped.

Ive been working on it for days and i cant get it to chrono higher than 200 fps and thats with an m100 spring, and aka gels. With the spring it came with, 140fps

It Had fake 18:1 shs gears, a FB polycarb piston, yellow ak poms head, green oring, lonex AR latch, (spring on that failed and let the box reverse and destroy tappet and the gear box housing) and a chihai black and red 35k rpm 460 motor

Shimming was potentially off, was very different after I replaced the gearbox housing

i had to adjust the pinion height as the pistol grip base is shite, motor always ran hot as did the battery. Motor has since failed.

Left motor is the motor it came with after I adjusted the pinion height as much as I wanted to, motor on the right is the stock motor.

Poms head was too big for the system and was very very tight. Has stretch the green oring and its useless

I found the hand guard grub screws over tightened, and have marked the inner barrel. Inner barrel wouldnt move freely on reciever. T-piece was glued to gearbox at some stage. End was covered in glue

Swapped tappet with ldt v3 orange tappet from xforce (same profile). System feeds

Swapped chihai with my stock 480 motor from the xyl arp9, and battery no longer gets hot, (was always hot even after shimming.

FB piston wouldnt take the spare heads i had so its running the stock xyl piston, piston head and oring for now. Head has been slightly modified for flow. Confirmed airseal and no vacuum with a gen9 head on the cylinder in the system. It still has the stock head which is leaky, even with TPFE tape.

Heres the odd thing. Its not the head. I have pulled a head and nozzle out of one of my spare cymas, checked and it chronos at 260 with a 1.18 ausgel. Yeah thats low, but the same head and spring in this system is 120-150fps

Im at a loss. Ive tipped maybe 20hrs on this and pulled it apart so often that im on the verge of stripping the thread on the pistol grip for the base plate.

Sooo … anyone seen this before?

AND, does anyone know if the ldt/war interest v3 box will drop into this?

Are you getting a good nozzle to t piece seal?

As i have 3 othe cymas, i swapped the upper receiver completely inc inner barreal abd t-piece. No change

I have the head, nozzle and upper receiver with inner barrel from the donor blaster on it and no change.

After ptfe tape gained 10fps

I thought doing the above with swapping the uppers over would give me an indication of that or not. No change leads me to think its not that

The upper from the blaster in question on my donor blaster chronos fine.

I think

Ive spent sooo much time on this i don’t remember

Swapping uppers doesn’t specifically test the t piece seal.

You should mate the t piece manually to the gearbox and blow through. With the tappet in it’s forward position.

If you have a good seal it should provide plenty of resistance

If it doesn’t have a good seal, how do i fix it?

As it stands right now, i have a new gearbox housing, different upper, brand new t-piece and an ausgel barrel.

The “spare” cyma is slowly getting upgraded so i can use it as the spare spare :wink:

M4a1 has the cyma metal cylinder head and nozzle for sale. Is it worth picking up one

The the mash of parts you listed, its possible you might need a different nozzle

If its a slight seal issue that just needs a little extra <0.3-0.5mm you could file the front of the tappet. Try a stiffer spring first.

Another cause is a soft, stretched or slightly longer tappet return spring

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That is something i haven’t checked, but its tappet is fully forward in the gearbox when i put it together, ot offers as much resistance as the other cyma box, and like i said, the head and nozzle from the working blaster is in it atm and no change.

Didnt think of that. Actually, ill swap the tappet out of the donor blaster and ill know for sure then

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or swap out gearbox into a working receiver may be different tolerances in the one with low fps gearbox housing may not be letting the nozzle go forward enough

check how far nozzle goes back and forward in both working and non working

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Sounds like a plan.

I personally would be interested is seeing if the ldt v3 box is a drop in. $80 for a metal gear gearbox that, since the t-pieces are technically interchangeable, should work.

You lose mag prime but thats a small price to pay i guess.

I need a break from it in all honesty. Ill have a look again at it tonight or tomorrow morning and ill report back.

The only reason im sticking with it is the knowledge i can impart, since every man and his dog now has one of these since tacedge was selling them dirt cheap, and you can’t actually buy just the tappet anywhere.

Hopefully the stock boxes comes back into stock soon

Agree with Hamish’s line of thinking.
It sounds like the issue is somewhere at the barrel-tpiece-nozzle-cylinderhead interfaces.

Your efforts appear to eliminate whatever is before the cylinderhead. The air being pushed out of the cylinder is not all going down the barrel.

Sometimes it can be that straightforward.

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Theres my problem. The original had the tail torn in 1/2, and since no-one has tappets and all the complete boxes are are sold out

The owner was sent with the busted one and was told this ldt one was the same profile. I took that at face value

At least its mystery solved.

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Would love to be blessed to buy blank tappets so you can profile them yourself

Would be nice. At least i know.

Ive seached and even over seas they dont seem to sell the tappet on its own.

Sacrificing my spare cyma to get it back online and out of my garage. Ill keep this ldt one, and see if I can modify to work

Maybe in a week or too see if i can order a couple of spare boxes

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Worst case should just be able to get an shs v2 tappet and profile it to suit. Shouldn’t be too much of a drama, glad to see you found your issue though :blush:

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Am going to profile the orange one to bring my blaster back to life. Later. Not now. Im blaster teched out.

Considering he was told this would do 280-290, and its running the stock nozzle and piston head with a bit of ptfe tap …

Fuck you blaster. I win.

Thats with milkies too. Not even akas. Messaged him then to see of he wanted to bring that back to 300 to keep it field legal

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Wtf. Why is all the photos im sending showing them rotated 90deg from what my iPhone has?

God damn apple shit

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Looks ok to me 🤷

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What did you do …

Every pic ive posted in the last day, ( since latest apple os update) has been rotated.

In the 2 at the top

Im guessing i need to turn off the live photo feature again …