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MINI blowback issue:

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Moving On
Oct 27, 2005
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KEE ACTION SPORTS

REWORK NOTIFICATION

Model: INVERT MINI

Problem:
Excessive air blowing by into feed neck area

Solution:
Enlarge air orifice in poppet using 0.7mm drill bit

Rework Procedure:
De-gas marker. Remove velocity adjuster from rear of marker body using ¼” hex wrench. Insert back end of a standard ball point pen down marker breach through bolt and push poppet out the back of the marker into palm of hand. DO NOT ALLOW POPPET TO FALL ONTO HARD SURFACE SUCH AS FLOOR OR TABLE as this can damage poppet sealing face. Place poppet in a soft jaw vice with side air orifice positioned straight up as shown in picture below. Enlarge hole indicated by the arrow using a 0.7mm drill bit. Blow debris from poppet using an air cleaning tool. Be sure poppet o-ring has a sufficient amount of grease before continuing. Insert poppet back into rear of marker with the plastic sealing face going in first. Push all the way in with the ball point pen until poppet stops. Then screw velocity adjuster in all the way until it stops, then back out exactly one full turn.

 

Robin Hood

Formerly Jermy
Feb 6, 2002
2,545
30
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An island in the rain
Edit:

Drefish on PbN said:
This "fix" should be only performed on markers with the blowback issue. If you do it to a gun that is working correctly you may lower your velocity or make it consume more gas. So it should only be done to guns with blowback. The size of the hole is critical.

Make sure you do NOT get lube in the small hole on the poppet!

With some guns in cold weather, or minutely different tolerances, or bad lubrication, or lube in the small hole (THIS IS VERY BAD, check for it and keep it clear!) or too small a hole, means the gas is released fractionally too soon from the poppet.

Making the hole larger releases the gas later, but it also allows more gas to go through the poppet and to the bolt, which may mean a decrease in efficiency or velocity on a gun that didn't need the change.

The increase in size to fix a gun with blowback is just 0.05mm which is just under 2 thousandths of an inch in diameter! Thats 0.0019" . Unfortunately brass is a soft material and so sometimes the holes vary slightly in size, or with temperature. Or they get a little lube or dirt in them...

You can not see this change with the naked eye. Attempting to do it yourself and drilling it oversize may result in a gun with low velocity and low efficiency, or even a gun that does not cycle.

If you have no blowback, you are fine... continue as you are. YOU do not want this change. If you have blowback then KEE will exchange the poppet. You DON'T want to change the poppet if your gun is working fine as is.

This is not an 'update' it is simply an adjustment to some guns and a way to make sure the gas release is at the correct point. Current guns with blowback can be fixed by replacing the poppet.

In the future KEE is working to make sure the gun's don't have blowback as they come from the factory. The criticality of the hole size has only come to light after getting many guns in the field, but it is an easy fix for you guys, and won't be an issue with new guns hopefully...
 

Panthro

LEGO 4 Life
Dec 30, 2005
374
30
48
Bristol
There is also another thread on the nation about the spring being to strong from stock. So this seems quite valid. Ain't received mine yet like. Ordered it just a waiting, hopefully won't have any board issues or poppit type valvey problems. Heres hoping!!!!!
 

onasilverbike

I'm a country member!
There is also another thread on the nation about the spring being to strong from stock. So this seems quite valid. Ain't received mine yet like. Ordered it just a waiting, hopefully won't have any board issues or poppit type valvey problems. Heres hoping!!!!!
Did find that the spring had to bed in (case of paint) before it would chrono consistently. Was going to ask what the serial #s for the blowback issue were, but if it's a limited amount of guns effected then I will leave it, seems fine. Btw, my serial is low 500's

:)
 

Jakey C

Jake Cross
May 28, 2006
341
1
28
wirral
Had the blowback issue crop up after using it for a while, bit weird really, went down during tourney so could do much. Under the understanding this was the same problem mine had i took it to an engineering place today and had them drill it. Will give it a go at the weekend and let you know results, Yes the spring does have to be bed in, few 1.1l tanks threw it on nxl should sort it, Dwell 28 BIP 3 are the settings im using atm