CYMA Thompson Problem HELP!

[lurky]

Hey guys,
I currently have a CYMA Thompson, mostly because I'm a WWII buff, but anywho, I had installed a 6.03 barrel into my gun just to see how it would last, and it worked great for about three months, no problems, it was a nice improvement. I had also heard from a lot of airsoft sites that a new hop up bucking may inrease accuracy too. They're cheap little things, I bought a madbull red bucking for about $6 off AirsoftGI. I strip down my gun, like I have countless times before while swapping barrels, no problem. I take out the barrel, the spacer and the bucking, no problem. I pop in the new bucking, everythings going smoothly. I reassemble the gun, take it out back, fire it once with the hop up all the way off, it goes about twenty feet, I turn the hop up up, but it doesn't make any difference. I turn it up all the way, still is shooting about only twenty feet. I take it back inside, strip it down, take out the barrel assembly, and nothing seems wrong. I put in the old bucking, I try it again, the gun still only shoots twenty feet. I strip it down once more, I even tried the madbull hop up spacer, but still, no results. when the barrel is outside of the gun, I can adjust the hop up and literally see the nub moving. I put it together, take it out back, shoot it, this time, its shooting two BBs at a time on semi automatic.

I'm sick of this thing at the moment. I've had a great experience with this gun over the past year and half, no problems whatsoever. Right now, I just really want my gun fixed. My only other gun is a Marui 552, but I really just love this Thompson. If any of you have any tips on how to fix it, please do tell!

[kalbs]

You have an air leak or no pressure either between the nozzel and hop-up at the hop-up it's self. Also, when you dry fire the gun does the nozzel move as it is suppose too? If not you have a broken tappet plate. Also, make sure you are setting the hop-up and inner barrel properly back into the AEG. If the hop-up sits to far away from the gearbox your pressure goes way down.

[lurky]

Yep, it seems to be a tappet plate, I think I'll have a local professional install it for me, I never wanna open up another gun for a while

[kalbs]

While they have the box open get the other stuff changed out like spring Guide, bushings (ver, 6 type), new PDI 170 spring, bearing spring guide, piston, piston head, cylinder head and nozzel...oh yes, and tappet.

[lurky]

Seems like this may get expensive
I think I found a couple of the parts you recommended, would these work:
Bushings: www.airsoftgi.com/product_info.php?products_id=171

Spring Guide:
www.airsoftgi.com/product_info.php?cPath=31_268&products_id=395

Spring:
www.airsoftgi.com/product_info.php?cPath=31_51&products_id=631

Cylinder set:
www.airsoftgi.com/product_info.php?products_id=5516

Piston:
www.airsoftgi.com/product_info.php?products_id=3135

Those sound about right? And what exactly will this all do for me?

[kalbs]

Apr 22, 2010 16:01:43 GMT -5 lurky said:

Seems like this may get expensive

Those sound about right? And what exactly will this all do for me?

Your Tommy will be better than before and much more durable which helps avoid break downs in the future.

[redvonhammer]

Probably just a minor problem..
I had the same problem after I installed some systema bushings and anti reversal latch /w spring on my CYMA Thompson (Because I was planning to install a Systema EG1000 engine as well, but redwolf sent me a faulty one.)

And so it turned out after closer inspection that I failed to reinstall the nozzle correctly, it was just a matter of lurking it onto the tappet plate. This was the first time I ever opened a AEG gearbox too, so I guess I was lucky, the ver.6 gearbox is also one of the simplest to work on


Also, a closer thought: Just taking the upper and lower receiver apart to change the barrel will probably do nothing to the tappet plate (Which is located inside the gearbox.) So I think you did nothing wrong, faulty tappet plate is normally just due to long usage without overhaul, I`m guessing you have used the gun for a while without overhauling it, which is completely understandable

As pointed out earlier, an overhaul would not be a bad idea, considering the possibility that the tappet plate or nozzle (Or both) might be worn out.

Sounds like you are not planning to upgrade FPS or RoF, so I think you`re of the hook with just normal overhaul by changing the bearings for the gears, (Systema makes some really good ones!) the piston, nozzle and tappet plate and otherwise just check if the other parts are good, grease the gears and bevel up a bit.. this doesnt cost much, you can do it yourself if you read up on some internet guides (Teaches you how your gun functions and is cheaper than paying someone else to do it) and will ensure the longevity and function of your gun

Good luck!