PX4: Diagrams and stripdowns?

[Garry]

As above, anyone got links for stripdowns and parts diagrams for the PX4 pistol?

Thanks a lot
Garry

[nidge.pidge]

Whatever you do, don't attempt to strip down this pistol!

Phil from a certain main distributor, who carrys out repairs on Umerex won't touch a PX4, due to complex nature of internals and springs that require tensioning to reassemble. Any faulty PX4s under warranty are replaced rather than repaired.

The CX4 on the other hand comes highly recommended as reliable and repairable!

[Garry]

It's alright, I've only had it a couple of days, so I won't be taking it apart.
I just like to know what's inside and how it works.
Thanks for the warning

[magicniner]

I'm so not impressed,
Really!

Looks like CO2 gunsmithing has descended to the depths of car mechanic work - glorified fitters unless the repair is easy and requires little or no understanding of function.

This

http://s135.photobucket.com/albums/q...view=slideshow

Is how to strip your PX4.
Maybe this guide would be of use to those claiming it's a full unit swapout only!

I don't recommend it unless you have a good grasp of general mechanisms and have worked on fiddly stuff before.

I firmly recommend taking photos, using magnetic trays to store springs and screws, use of organiser boxes to store parts and stripping unknown assemblies in a big clear bag.

Once you get to know your PX4 it's not a bad gun to strip, it's worth doing just to lighten the safety (it's actually possible but fiddly without removing ANY components)

I've stripped & reassembled mine four times without issues, I've stopped using Umarex pellets in it as a result as the shed so much crud into the mech.
Maybe I'm getting a little gung-ho in my old age but I don't like to use anything I can't strip & fix myself ;-)
Love the PX4, great fun to shoot, not sure if it will speed up or slow down my IPAS times but I plan to try it along with a 4" S&W and a tuned (by me) Skif A3000,
Have Fun!
Nick

[nidge.pidge]

I don't recommend it unless you have a good grasp of general mechanisms and have worked on fiddly stuff before.


Nick

Looks more like watch making skills required than gunsmithing!

The distributor has obviously decide that replacement is more cost effective than fiddly repairs! Doesn't mean that the necessary skills are lacking and I am sure that anyone who has had dealings with Phil can testify to his skill and knowledge of CO2 airgun repairs.

[Garry]

That's probably the best stripdown instructions I've seen, and on an easy to watch slide show as well!
It's a good job there are enthusiasts who take the time and trouble to do stuff like this, and it helps sales as I'd go for something with plenty of information available on it.

Do you reckon the slide lock could be made functional? It would need some way of knowing the mag was empty though

[magicniner]

Mark,
the frame where the lock fits has more detail than required, suggesting more function was planned, I think early promotional material mentioned a functional slide lock which never materialised.
Sensing an empty mag is an interesting one, you'd have to sense an empty slot adjacent to the barrel, not impossible but you're talking about building your own mechanism and adding this into the gun.
I'm interested in having the hammer cocking motion advance the magazine (rather than the first motion of the trigger) giving true semi-auto function.
Lots of other projects to complete first though
Nick

[Garry]

Let us know if you come up with anything
Cheers Nick

ATB
Garry

[Adam77K]

I don't have a PX4 but am watching this thread with interest. Nick if you get time to do what you say I'll be adding a "magicniner special" custom PX4 to my wish list!

[magicniner]

Don't hold your breath, I've just collected a JB1 Titan SSP rifle that requires a valve strip & rebuild
I might have a fettle though, now I have two working PX4s, my front gas valve seal replacement has been holding gas for 48 Hours
Nick

[vfrkid]

Have you ever worked on a CP99 compact? it looks similar inside, I have two, one works fine and the other is very low on power and will not blowback fully, All the components in the valve look OK, and the slide runs smoothly.

[magicniner]

VFR, (ZX9R man myself )
I've not fiddled with a CP99 but a combination of low power and inadequate blowback suggests the valve may not be opening enough or something is restricting gas flow.

Is the valve action sticky or stiff? Check without gas & clean & lube everything with silicone oil.

Is the hammer system hitting the valve cleanly and as hard as it's supposed to?

Are you using caplets with lube or using pellgun oil if not? Don't run the gun dry.

Are the caplets pierced cleanly & fully? If not check the differences with the working gun.

Have you stripped & checked the inlet side of the valve for dirt & obstructions? There's a filter in most CO2 guns to stop debris getting into the valve, this can clog up over time.

Let me know how it goes,
Regards,
Nick

[vfrkid]

Hi was a VFR in 2003..a speed triple now,did have a ZX7R before that.

Is the valve action sticky or stiff? Check without gas & clean & lube everything with silicone oil....... I have done.

Is the hammer system hitting the valve cleanly and as hard as it's supposed to?.....seems the same as the working one.

Are you using caplets with lube or using pellgun oil if not? Don't run the gun dry.......yes

Are the caplets pierced cleanly & fully? If not check the differences with the working gun........No the capulets are not piercing fully, but the pressure is getting into the valve, if I press the valve stem manually it dumps all the gas from the capulet.

Have you stripped & checked the inlet side of the valve for dirt & obstructions? There's a filter in most CO2 guns to stop debris getting into the valve, this can clog up over time.......No but I have blown down it with a small tube and the air is comming out into the valve body.

[magicniner]

You've covered all the bases, without taking a look I can't think of anything further, if you're coming to the next UBC meet and don't have it sorted by then I'll bring my tools & have a look.
You could swap gas blocks between guns & see if the problem follows gun or block, same principle will work with any other component or assembly,
Regards,
Nick

[vfrkid]

Cheers, I'll take another look at it when I have time, dont want to muck about with the good one as it fires nicely, have swapped slides though.