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Hop Up acting funny


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#1 Twotone1487

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Posted 13 October 2013 - 12:01 PM

Hey KWA Forums, I just bought a KWA KM4 Commando. I received it and immediately noticed the hop up wasn't very effective. I looked through the forums and found the threads on cleaning. I took apart the hop up, cleaned the bucking and barrel of all grease/oil and put it back together. I have since noticed 2 things. 1. the hop up seems to walk. Although I haven't done a thorough test, it seems to be moving positions. 2. It seems to take a while before the hop up begins to put spin on the bb. It takes about 10-20 rounds for the hop to start working. After it isn't used for a while, you have to send the same 10-20 rounds down range again to get the hop working again. Anything that could help would be very much appreciated. Thanks! Oh, and I am a new KWA owner and it's great to have such an awesome resource like these forums. Thanks to everyone who regularly checks and is willing to help!

#2 gcw360

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Posted 13 October 2013 - 04:55 PM

View PostTwotone1487, on 13 October 2013 - 12:01 PM, said:

Hey KWA Forums, I just bought a KWA KM4 Commando. I received it and immediately noticed the hop up wasn't very effective. I looked through the forums and found the threads on cleaning. I took apart the hop up, cleaned the bucking and barrel of all grease/oil and put it back together. I have since noticed 2 things. 1. the hop up seems to walk. Although I haven't done a thorough test, it seems to be moving positions. 2. It seems to take a while before the hop up begins to put spin on the bb. It takes about 10-20 rounds for the hop to start working. After it isn't used for a while, you have to send the same 10-20 rounds down range again to get the hop working again. Anything that could help would be very much appreciated. Thanks! Oh, and I am a new KWA owner and it's great to have such an awesome resource like these forums. Thanks to everyone who regularly checks and is willing to help!
Hi Two tone, welcome to the KWA Forums.  Her's what I would do.
  • Tighten the screw on the hop-up adjustment wheel so that it stays set when you turn it
  • Take a small piece of wire, the same length as the nub is wide, and put it in the hole in the nub.  I can almost guarantee you the issue will be solved with this simple mod.
Let us know how it works out.

#3 Twotone1487

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Posted 13 October 2013 - 06:35 PM

Thanks, gcw360. I will try that as soon as I can. I really appreciate it!

#4 Twotone1487

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Posted 14 October 2013 - 07:43 PM

View Postgcw360, on 13 October 2013 - 04:55 PM, said:

Hi Two tone, welcome to the KWA Forums.  Her's what I would do.
  • Tighten the screw on the hop-up adjustment wheel so that it stays set when you turn it

  • Take a small piece of wire, the same length as the nub is wide, and put it in the hole in the nub.  I can almost guarantee you the issue will be solved with this simple mod.
Let us know how it works out.


Alright, so I did tighten up the hop and that works just fine. I did add a piece of wire in the nub. It seems to help a little, but I still have to fire a few rounds before I notice the hop up work. Could it be the bbs I'm using? I have been testing it with Lancer Tactical competition grade .25s.

#5 gcw360

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Posted 15 October 2013 - 09:10 AM

View PostTwotone1487, on 14 October 2013 - 07:43 PM, said:



Alright, so I did tighten up the hop and that works just fine. I did add a piece of wire in the nub. It seems to help a little, but I still have to fire a few rounds before I notice the hop up work. Could it be the bbs I'm using? I have been testing it with Lancer Tactical competition grade .25s.
Never heard of them....My guess is there is grease in the bucking though.  Take a Q-Tip and swab the bucking while turned fully on.  Swab where you see the protrusions inside the inner barrel.  Is the Q-Tip dirty?  After that I would try some other BBs too.

#6 niko_gpsy

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Posted 16 October 2013 - 10:54 AM

I agree with gcw.
Even a little bit of grease can cause very poor hop up performance.  When new, the bucking and barrel will need frequent thorough cleaning during the break in period where excess factory gear grease can shoot  out contaminating the bucking contact surface.

#7 Twotone1487

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Posted 16 October 2013 - 06:02 PM

View Postniko_gpsy, on 16 October 2013 - 10:54 AM, said:

I agree with gcw.
Even a little bit of grease can cause very poor hop up performance.  When new, the bucking and barrel will need frequent thorough cleaning during the break in period where excess factory gear grease can shoot  out contaminating the bucking contact surface.

View Postgcw360, on 15 October 2013 - 09:10 AM, said:

Never heard of them....My guess is there is grease in the bucking though.  Take a Q-Tip and swab the bucking while turned fully on.  Swab where you see the protrusions inside the inner barrel.  Is the Q-Tip dirty?  After that I would try some other BBs too.

Thanks a ton guys! I am trying this all out. I also ordered a 2nd bucking to see if this helps the issue. Again, thanks I really appreciate it!

#8 niko_gpsy

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Posted 17 October 2013 - 04:07 AM

If cleaning or a new bucking doesn't resolve the issue try using a harder nub.  You can insert a piece of wiring or anything hard in the center of the nub cut to length if you can't find anything online.

#9 Twotone1487

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Posted 17 October 2013 - 06:43 PM

Hey guys,

It was indeed the bucking. So the old one has to have some residual oil on it. The new bucking works flawlessly. So thank you niko and gcw!! Again, I appreciate everything.

#10 gcw360

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Posted 18 October 2013 - 08:39 AM

View PostTwotone1487, on 17 October 2013 - 06:43 PM, said:

Hey guys,

It was indeed the bucking. So the old one has to have some residual oil on it. The new bucking works flawlessly. So thank you niko and gcw!! Again, I appreciate everything.
Our pleasure!




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