V3 gearbox/hop issue?

[Randymanpipe]

Hi all,

 

A while ago I did some work on my JG RPK. I replaced the stock hop unit for a combat union, purple prommy bucking & nub installed the combat union nozzle that came with the hop.

Cleaned out the v3 gearbox and re greased.

 

It has been great (around 2yrs) but has recently started having this weird issue where every 6th or 8th round out comes out like 60fps while all the others are around 330fps. Does it on full auto and semi. Have tried brand new mid caps as well as the drum mag I usually run on it. Any ideas what could be causing this?
 

Wondered if it is a hop issue? Nozzle? Tappet plate? Timing issue? I don’t know where to start? 
any advice would be most welcome and appreciated ☺️

Thanks in advance 

 

happy hunting 

Edited May 14 by Randymanpipe

[gavinkempsell]

I'll preface this by saying... I know F/A about ANYTHING but it sounds like the nozzle is sticking preventing a good air seal, possibly too much grease going where it shouldn't be? give it another clean.

[Sewdhull]

Well at 60 fps the nozzle to bucking relationship is losing the air. I'm assuming all else is well.

 

So your options are worn or broken tappet plate, nozzle or bucking. Nozzles get wear inside and at the tip whacking the bbs all the time, tappet plates wear on the fin and buckings get worn lips...

 

Inconsistent air seal issues often fall to the nozzle and bucking meeting offline due to wear and then things get gradually worse. If a bb always comes out that's where I would start and just replace both the nozzle and bucking with the same thing as is there already.

[Skara]

When I still had the E&L I had a combat union hop unit inside and the nozzle was very tight on the cylinder head.. I didn't have power loss nor any feeding issue that wasn't magazine related.

Mind you mine was a gen 1 CU hop.

 

Maybe it's tight on your setup as well and this being tight prevents the nozzle from sealing from time to time.

 

If you're in for a fancy (and expensive) hop up I would suggest the begadi ones, they are fantastic and you're not limited to ONE nozzle. They list compatible guns on the website for both options (green: cyma spec, blue: E&L spec)

[Colin Allen]

14 hours ago, Skara said:

When I still had the E&L I had a combat union hop unit inside and the nozzle was very tight on the cylinder head.. I didn't have power loss nor any feeding issue that wasn't magazine related.

Mind you mine was a gen 1 CU hop.

 

Maybe it's tight on your setup as well and this being tight prevents the nozzle from sealing from time to time.

 

If you're in for a fancy (and expensive) hop up I would suggest the begadi ones, they are fantastic and you're not limited to ONE nozzle. They list compatible guns on the website for both options (green: cyma spec, blue: E&L spec)

I would second the recommendation of the Begadi hop units; superb!