Hop-up problem

[yuhaoyang]

So I have a G&P mechbox (metal nozzle) and a modify one piece hop-up chamber with classic army hop-up rubber and inner barrel, everything cycles fine, no misfeeds, fires correctly and ect. However, when I fire a 3-4 round burst on full auto, a BB comes rolling out of the barrel, the hop-up has been cranked to the max, and that problem still happens, also, it seems to be ineffective, as the BBs will start falling at the same distance with or without hop-up. The rubber does not have any grease on it, and the bucking is in the right place and everything. The gun shoots a 320fps steadily, so there should be no compression problem. Any one have this problem before?

EDIT: turns out gearbox isn't cycling properly, the piston gets pulled back by 1 gear notch every semi shot. Hmm... cut off lever problem perhaps? I've tried 2 cutoff levers and they both result in the same thing.

[Skladfin]

send it to me, ill fix it up

[namloot]

Sounds like the nub is missing.

[Shirley]

You can even make your own nub yourself lol.

[yuhaoyang]

The thing that looks like 14 guage wire silicone covering? I got that in place already.

[Shirley]

That little nub.

[yuhaoyang]

got it

[coach]

Originally Posted by yuhaoyang

The thing that looks like 14 guage wire silicone covering? I got that in place already.

is it in installed in the right direction?

[Shirley]

Originally Posted by yuhaoyang

got it

YouTube - replacing the hopup on an airsoft gun

[yuhaoyang]

It might be becasue the nub is too weak. I turned the hop-up to full, then used an allan-key to push it up, it retracted without much force. I will get another nub and see how it goes. Thanks for all the help so far.

[Shirley]

You can make your own nub with basically anything that holds and rolls. Writing paper to electrical tape. I used electrical tape because it holds better.

[Spa]

im sorry to say but that video is not the best way to replace a rubber

I usually unscrew everything and take the nub out first. Then i make sure to bend the hop up like he did. I just pull the rubber out with the barrel by some good twisting to prevent tearing or stretching or damage. It is so much easier with everything apart.

+1 for the prom rubber

PS: I think he likes his cat.

[Mikhail]

On my Ak hopup, I can insert the hopup bump after the hopup tube is installed by removing the hopup pressure lever (?) first, inserting the bump under the lever and replacing the lever...would this help him out if he has a different hopup?

I too have hopup troubles...but I am pretty sure the rubber tube is dying as I see rubber residue in my inner barrel after firing...problaly need a hard rubber houp.

But as a result of MY issues, I have spent a wee bit of time becoming familiar with my hopup unit. So I am doing ok.

Hope that helps a bit with your troubles.

[m102404]

Even in semi, it's normal for the piston to be drawn back a bit before it stops...the main spring pressure and the resistance of the motor are the only thing stopping the gears from rotating after the power is cut and there's still spinning momentum in the gears. Ideally, it should stop at about the same point after each semi shot. Don't worry about that.

I would suggest that you consider replacing the hopup unit. I've only used a couple of the modify one-piece metal hopup units and I couldn't get them to shoot well in the 3-4 builds that I tried before I scrapped them. Too bad because they looked good and were priced nicely. Same thing with sort-of jamming, wonky FPS. For me they'd usually blank fire then double shot the next trigger pull. Swapped out for either a G&P or KA Enhanced and zero issues with all of those builds. I tried over and over with the Modify hopup until I just threw it out.

With the inner barrel, hopup rubber, nub and hopup unit assembled...you should be able to see the "lip" of the hopup rubber seated nicely in the hopup unit (no bunching...nice even ring of rubber). Turning the hopup on or off...you should see the nub evenly push down into the barrel and raise back up.

To install the nub, turning the hopup upside down and poking the nub with a thin pick until it seats in the notch is fine. Taking it apart and putting it under the hopup arm while the barrel/rubber is already in place is fine to...but I always worry about the little screw that holds the main adjustment wheel in place snapping....I had it happen on 2 KA Enhanced units (BNIB)...and unless you can get the screw shaft out, you've just pooched a perfectly good hopup unit.

[Mikhail]

My apologies for straying off this fellows question, but if I may ask, what Hopup unit DO you recommend...is the plastic Modify hopup better than the metal one you mention? Airsoftparts.ca is probably who I would get it through.

I was considering upgrading the entire hopup and was considering the metal version, until I saw your post about your experiences with it.