Marui hopup jam

[BKHKMP5]

I installed a Gaurder SP120 upgrade kit into my MP5. It's pretty much the first time I've had it running properly after putting the whole thing up together. Here's the problem. There seems to be some sort of plastic thingy inside the hopup tube. Is this normal. It's right after where the bb's are fed into the barrel from the magazine. If I poke it this flap moves out of the way, it seems really loose. If I try to fire, the bb just gets stuck and doesn't pass the flap. I used a screw driver and poked around till the flap went away. My gun then fired just fine. After about 30 shots, that stupid flap came back down and jammed the bb's again. Any idea what's going on? Is this flap supposed to be there or is there something broken inside my hopup. I'd rather just remove the flap if possible. Thanks,

Bryan

[six4]

Originally Posted by BKHKMP5

I installed a Gaurder SP120 upgrade kit into my MP5. It's pretty much the first time I've had it running properly after putting the whole thing up together. Here's the problem. There seems to be some sort of plastic thingy inside the hopup tube. Is this normal. It's right after where the bb's are fed into the barrel from the magazine. If I poke it this flap moves out of the way, it seems really loose. If I try to fire, the bb just gets stuck and doesn't pass the flap. I used a screw driver and poked around till the flap went away. My gun then fired just fine. After about 30 shots, that stupid flap came back down and jammed the bb's again. Any idea what's going on? Is this flap supposed to be there or is there something broken inside my hopup. I'd rather just remove the flap if possible. Thanks,

Bryan

that would be your hop-up bucking you are stabbing at with a screwdriver,,and it is adjust to the all the way on position,,thats what you are seeing. the "hop-up" is what puts backspin to the bb as it is fired from the barrel,,,kinda the same way you would shoot a basketball,,,with backspin as it leaves your hands,,,same idea. this gives your bb the truest flight possible. now,,just above the foregrip close to the outer barrel you will see a small 2-3 mm lever,,that would be your hop-up adjustment. back it all the way off and adjust it according to how the bb flies. the straightest and truest flight is what you want to achieve. keep in mind it is still a bb gun and anything can hinder the bb's flight time.

(p.s.) here's a pic of the hop-up lever.

http://i41.photobucket.com/albums/e2...hopuplever.jpg

(p.s.s.) and for poking at your hop-up bucking with a screwdriver,,you are not called "bryan" anymore,,you have earned the nickname "BARNYARD" ( joking)

[BKHKMP5]

That's not it. I know what you're talking about. When I adjust the hop-up lever I can see a small tab inside the barrel moving up and down, but it only covers about 10% at most of the inner barrel. This flap that's blocking the inside isn't the hopup, it's a funny looking thing that covers the entire inside of the barrel, it has smal holes inside, difficult to explain but it's basically a round flap and can be pushed out of the way but then seems to retract when you let go. I thought at first that the nozzel was supposed to push this flap out of the way before it fires, but it just keeps getting jammed. Like I said, once I push it out of the way, the gun fires fine, but it keeps getting back in the way.

thanks,

[six4]

Originally Posted by BKHKMP5

That's not it. I know what you're talking about. When I adjust the hop-up lever I can see a small tab inside the barrel moving up and down, but it only covers about 10% at most of the inner barrel. This flap that's blocking the inside isn't the hopup, it's a funny looking thing that covers the entire inside of the barrel, it has smal holes inside, difficult to explain but it's basically a round flap and can be pushed out of the way but then seems to retract when you let go. I thought at first that the nozzel was supposed to push this flap out of the way before it fires, but it just keeps getting jammed. Like I said, once I push it out of the way, the gun fires fine, but it keeps getting back in the way.

thanks,

anyway you could post a picture of the problem? perhaps the hop-up sleeve has torn.

[BKHKMP5]

Originally Posted by six4

anyway you could post a picture of the problem?

I'll try my best, but I probably won't be able to take pics of inside the barrel.

BTW, is there supposed to be anything inside the barrel/hopup that blocks the barrel? Aside from the hopup. This flap seems to block the entire barrel.

[six4]

[QUOTE=BKHKMP5;461262]I'll try my best, but I probably won't be able to take pics of inside the barrel.

BTW, is there supposed to be anything inside the barrel/hopup that blocks the barrel? Aside from the hopup. This flap seems to block the entire barrel.[/QUO

unless its some form of inner barrel velocity reducer,,i cant see anything other than the hop-up being in there.

[Iggy]

could be the nozzle? Did you try taking out the hopup unit itself... take out the barrel and readjust the rubbers...

[BKHKMP5]

Originally Posted by Iggy

could be the nozzle? Did you try taking out the hopup unit itself... take out the barrel and readjust the rubbers...

I have removed the hop up. There was a metal teeth washer that was holding the actual hopup together that I didn't want to remove. I would have broken it. Anyways, what rubbers are you referring to?

[ILLusion]

Sounds like your hop up rubber's outer lip is torn and getting in the way of the feed path. I've seen it a couple of times, but never figured out what causes it.

[six4]

Originally Posted by BKHKMP5

I have removed the hop up. There was a metal teeth washer that was holding the actual hopup together that I didn't want to remove. I would have broken it. Anyways, what rubbers are you referring to?

it looks like this.
http://www.wgcshop.com/pcart/shopper...-HUB_cat_Marui Parts
a small rubber/silicone sleeve that fits over the inner barrel

[CDN_Stalker]

Oh boy.

Just buy a new hop up rubber for it and install it. You ripped the stock one, it's causing your problems (likely from not lubing the hop up/loading tube every thousands shots or so, feed lip gets sticky, BB gets shoved through, rips the soft rubber........... nuff said.) Order a Guarder clear hop up and packing, WGC or other company, best I've found in Canada is Airsoft Kelowna, $9CDN, cost you $20 to your door. Both my MP5s have that installed and work great, better than stock.

[BKHKMP5]

I removed the hopup today and the rubber was torn. I replaced it with a silicon sleeve. Now I have a new problem. The torn sleeve was one of the problems, but now my gearbox nozzle is acting up. It's supposed to spring back if I push it in correct? It doesn't. It still pushes outward when I fire, but it stays in the in position and I can't push down on it. The reason this is a problem is because the bb's are still stuck when I fire. I think the nozzle isn't moving out far enough to push the bb's through the hopup sleeve. Sound right to anyone? This is only an assumption. But Brian (Illusion) tells me that the nozzle should be able to be pushed down on and spring back everytime. I'm going to have him take a look at it later in the week, but for the time being, any ideas on what I can try?

Thanks,

Bryan

[brently0725]

The tappet plate in the mechbox is what controls the nozzel on you MP5. I have broken a few tappet plates before and this, to me, sounds the same. If you have not opened your mechbox before DON'T do it yourself. Get someone to help you. The tappet plate rides on a gear and every cycle it moves in to allow a bb to enter the hop up in your gun. If you do open the mechbox yourself beware it might blow apart on you. Search for a video guide or website on how to open a Version 2 mechbox before you start!!!! Do some research please!!



ILLUSION IS YOUR BEST BET!!! HE SOUNDS VERY KNOWLEDGABLE!