MP7 Problem, Gear Timing

nic_s · April 21st, 2006, 19:50

I got my MP7 when they first came out, and I bought it new. Since day one though, it's had some troubles. When firing on full-auto, the BBs would usually just drop out of the barrel and fly about ten feet. Semi-auto was better but it would often have the same problem. Not all the time though, which is strange. Now, when it does this, the gun sounds like it's dry firing. This makes me think that the nozzle is retracted when the piston moves forward to push the air out of the cylinder.

So, I took the gun apart, and upon inspection of the gearbox I have found that the gear timing apears to be off from the factory, since the nozzle was about half way back at 'zero'.

After opening the mechbox, I also found that the damping foam on the cylinder head was partially torn, and there was a chunk that was about to break free. I removed all the damping foam, since the asymetric nature of the torn foam would probably affect accuracy. That's a minor detail though. The main issue here is ger timing.

So: Has anyone here had similar issues? How did you fix it? Any thoughts or theories?

mcguyver · April 21st, 2006, 20:39

So, how did you fix the "timing problem"?

oOMuDOo · April 21st, 2006, 21:25

It only did that to me when the battery was weak.

Blackthorne · April 21st, 2006, 21:34

In my experience, there is no such thing as "gear timing". The gears reset to "zero" after the completing one cycle.

Ghost Snake · April 21st, 2006, 22:18

I dont know how many times people have to say it, but, THERE IS NO SUCH THING AS GEAR TIMING. If you have any mechanical sense whatsoever, this should be very evident the first time you take a mech box apart. Your problems are coming from somewhere else.

Blastyman · April 21st, 2006, 23:39

LOL

Anyhow yeah I had the same problem with mine. till I lubed up the mags and fires great now

nic_s · April 22nd, 2006, 16:15

No such thing as gear timing? Maybe I'm not explaining this right... Sorry if my terminology is off here.

I'll put it together again with the loading nozzle/tappet plate all the way forward, i.e. the sector gear is not actuating the tappet plate at all.

nic_s · April 23rd, 2006, 05:38

OK, re-assembled the mechbox today, did a test run, and for some reason the piston got completely chewed. The entire first tooth is cracked off. No idea why, although I have heard of other people chewing up MP7 pistons.

This is really getting frustrating...

thePiRaTE!! · April 23rd, 2006, 05:53

Just to add another .2 cents - when i first got mine, I had issues with BB's just plopping out or firing wildly. Same as Blastyman mentions, I tried a little silicone spray in the loading rod before filling it with BB's, which in turn lubed up the mag, its been 100% ever since. Hope it helps! (after you get a new piston...)

nic_s · May 3rd, 2006, 06:46

[bump]More input anybody?[/bump]

jtf2-phalanx · May 3rd, 2006, 21:14

Quote:

Originally Posted by Ghost Snake

I dont know how many times people have to say it, but, THERE IS NO SUCH THING AS GEAR TIMING. If you have any mechanical sense whatsoever, this should be very evident the first time you take a mech box apart. Your problems are coming from somewhere else.

Sorry for the thread jack but you've gotta love it when people regurgitate what others have said yet don't offer any solution other than, "the problems are coming from something else". Sorry for the rant.

oOMuDOo · February 5th, 2007, 21:25

Nic,

Did you ever get this fixed? I seem to have the same issue.

EDIT*** Hummm, I cleaned out the berrel and lubed it up some more. Seem to be working better now.

Man this gun is worse than a woman.

johnnyrico · July 18th, 2007, 08:45

All aep's suffer from the same problem.

When ever the, not feeding / bb's dopping / no distance or power thing comes up...

Just fill a mag with bb's, put a few drops of light weight silicone oil on the top bb in the mag.

Presto, problem solved.

As for the chewed piston.... that sux. Sorry.

Kos-Mos · July 18th, 2007, 11:25

your piston problem is quite obvious...

you removed the foam on the face of the piston head.... so your piston was always too far foward when the sector gear catch the first tooth, so it is slipping every cycle..

get a new piston head

Spa · July 18th, 2007, 12:13

yeah, you should be able to push the piston all the way foward in the cylidner till it stops(including cylidner head), then you should check to see if the sector gear grabs the first tooth.

Yeah if your ripping stuff off teh piston head, things are gonna hit the fan man

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April 21st, 2006, 19:50	#1
nic_s Trader rating Join Date: Oct 2004 Location: BC	MP7 Problem, Gear Timing I got my MP7 when they first came out, and I bought it new. Since day one though, it's had some troubles. When firing on full-auto, the BBs would usually just drop out of the barrel and fly about ten feet. Semi-auto was better but it would often have the same problem. Not all the time though, which is strange. Now, when it does this, the gun sounds like it's dry firing. This makes me think that the nozzle is retracted when the piston moves forward to push the air out of the cylinder. So, I took the gun apart, and upon inspection of the gearbox I have found that the gear timing apears to be off from the factory, since the nozzle was about half way back at 'zero'. After opening the mechbox, I also found that the damping foam on the cylinder head was partially torn, and there was a chunk that was about to break free. I removed all the damping foam, since the asymetric nature of the torn foam would probably affect accuracy. That's a minor detail though. The main issue here is ger timing. So: Has anyone here had similar issues? How did you fix it? Any thoughts or theories? __________________ ...and she's terribly partial to the periwinkle blue.

April 21st, 2006, 20:39	#2
mcguyver Trader rating Join Date: Aug 2005 Location: Northern Alberta	So, how did you fix the "timing problem"? __________________ Age verifier Northern Alberta Democracy is two wolves and a sheep discussing what's for dinner. Freedom is the wolves limping away while the sheep reloads. Never confuse freedom with democracy.

April 21st, 2006, 21:25	#3
oOMuDOo Trader rating Join Date: Apr 2004 Location: Cochrane, AB	It only did that to me when the battery was weak. __________________

April 21st, 2006, 21:34	#4
Blackthorne A Total Bastard Trader rating Join Date: Jun 2005 Location: Consecon, Ontario	In my experience, there is no such thing as "gear timing". The gears reset to "zero" after the completing one cycle. __________________ VINCITE OMNIMODO

April 21st, 2006, 22:18	#5
Ghost Snake Trader rating Join Date: Apr 2005 Location: Edmonton	I dont know how many times people have to say it, but, THERE IS NO SUCH THING AS GEAR TIMING. If you have any mechanical sense whatsoever, this should be very evident the first time you take a mech box apart. Your problems are coming from somewhere else. __________________

April 21st, 2006, 23:39	#6
Blastyman Trader rating Join Date: Feb 2003 Location: Edmonton ,AB	LOL Anyhow yeah I had the same problem with mine. till I lubed up the mags and fires great now

April 22nd, 2006, 16:15	#7
nic_s Trader rating Join Date: Oct 2004 Location: BC	No such thing as gear timing? Maybe I'm not explaining this right... Sorry if my terminology is off here. I'll put it together again with the loading nozzle/tappet plate all the way forward, i.e. the sector gear is not actuating the tappet plate at all. __________________ ...and she's terribly partial to the periwinkle blue.

April 23rd, 2006, 05:38	#8
nic_s Trader rating Join Date: Oct 2004 Location: BC	OK, re-assembled the mechbox today, did a test run, and for some reason the piston got completely chewed. The entire first tooth is cracked off. No idea why, although I have heard of other people chewing up MP7 pistons. This is really getting frustrating... __________________ ...and she's terribly partial to the periwinkle blue.

April 23rd, 2006, 05:53	#9
thePiRaTE!! Trader rating Join Date: Aug 2005 Location: Calgary	Just to add another .2 cents - when i first got mine, I had issues with BB's just plopping out or firing wildly. Same as Blastyman mentions, I tried a little silicone spray in the loading rod before filling it with BB's, which in turn lubed up the mag, its been 100% ever since. Hope it helps! (after you get a new piston...) __________________

May 3rd, 2006, 06:46	#10
nic_s Trader rating Join Date: Oct 2004 Location: BC	[bump]More input anybody?[/bump] __________________ ...and she's terribly partial to the periwinkle blue.

February 5th, 2007, 21:25	#12
oOMuDOo Trader rating Join Date: Apr 2004 Location: Cochrane, AB	Nic, Did you ever get this fixed? I seem to have the same issue. EDIT*** Hummm, I cleaned out the berrel and lubed it up some more. Seem to be working better now. Man this gun is worse than a woman. __________________ Last edited by oOMuDOo; February 6th, 2007 at 08:30..

July 18th, 2007, 08:45	#13
johnnyrico Trader rating Join Date: Apr 2002 Location: Winnipeg, MB	All aep's suffer from the same problem. When ever the, not feeding / bb's dopping / no distance or power thing comes up... Just fill a mag with bb's, put a few drops of light weight silicone oil on the top bb in the mag. Presto, problem solved. As for the chewed piston.... that sux. Sorry. __________________ "Banning firearms to prevent criminal use of guns is about as smart as banning marriage to prevent spousal abuse, or banning pregnancy to prevent child abuse. " "When just seconds can mean life or death, the police are just minutes away" "If you can read this, thank a teacher... Since it's in English, thank a soldier"

July 18th, 2007, 11:25	#14
Kos-Mos Trader rating Join Date: Nov 2005 Location: Lévis (QC)	your piston problem is quite obvious... you removed the foam on the face of the piston head.... so your piston was always too far foward when the sector gear catch the first tooth, so it is slipping every cycle.. get a new piston head

July 18th, 2007, 12:13	#15
Spa Trader rating Join Date: Oct 2006 Location: Winnipeg, Manitoba	yeah, you should be able to push the piston all the way foward in the cylidner till it stops(including cylidner head), then you should check to see if the sector gear grabs the first tooth. Yeah if your ripping stuff off teh piston head, things are gonna hit the fan man

MP7 Problem, Gear Timing

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