TM m4 cycle problems.

[Reincarnation...]

-TM M4 RIS with G&P Zombie Killer Body

-Guarder 110 spring (360-370fps)

-CA stock gears

-Area 1000 Duracon Piston Head

-Area 1000 Polycarbon Piston

-Guarder Spring Guide

-Rewired to the back with deans

-Battery is 9.6 1700mAh crane battery.

 

Now that you have my specs, here is my problem. In full auto its can do a burst but then will get the internals locked with no action or cycling. In semi-auto if the trigger is half pulled the mechbox locks. However if it is locked when doing a full auto burst, I can just go back to semi-auto, pull and its fine afterwards until I go back and try to do a burst in full-auto. So far I been just using it in semi at this moment and would like to fix it and this one issue. Thanks in advance.

[Rattler]

Hmm.... did you notice a drastic decrease in FPS after any of the upgrades? (specifically the gears or wiring).

 

Is it louder after the upgrades, more of a whining sound to it?

 

The gears could be shimmed badly or timed badly. It could also be a wire not set in the proper position when it was wired to the back and it may be interfiering with the selector area of the gun.

 

How long ago did you perform the upgrades? did YOU personally do the upgrades?

 

It sounds more than anythink else like it is something not coordinated properly rather than a wiring issue, however your answers to the above questions can tell a lot.

 

 

Thanks

Dan

[Svack]

I would say shims are most likely the cause of your problem

I had a similar problem when I overshimmed my gears

[Rattler]

I would say shims are most likely the cause of your problem

I had a similar problem when I overshimmed my gears

 

 

I also had this problem a lot when I first started shimming a few years back. However, it may also just be the timing of the gears not set properly and the gun would still fire just at the same speed. That is why I ask if the ROF went down at all or if it got louder, that is always how you can tell if it is faulty shimming.

 

When I put a gearbox together when I finish work on it, I always run a few tests before I put the gun back together.

 

First,

I make sure all the screws holding the gearbox are tightly fastened. Then I take a small, flat headed screw-driver and try moving the bevel gear. If it moves freely (freely meaning you can give it a push and it can use momentum to spin on it's own) then the gun is either shimmed perfect OR too lightly. Either way it is not too tight and the above problems would be from shimming being too tight.

 

If the gears are hard to move and can not move freely, the the gun is shimmed too tight, timed badly or there is a problem with one of the gears (most likely of the three is too tight of shimming).

 

Second,

I push the nozzle in a few times, just to make sure it goes in without a whole heck of a lot of force and can return to its original position on it's own freely. It may take a bit of a push when you are pushing it the first time. If it does, just give it a little (but not too much) more force and it should pop and then go back and forth normally. If it does not pop, then you assembled something wrong and need to go back in the gearbox and make sure everything it set right and try again.

 

 

Third,

I then take an allen wrench or a small screwdrive, stick it UP the nozzle so it will go to the piston head, and push the piston backwards and let it push back forwards, just to make sure it is sitting in the proper position. If it does not go back, just apply a little (not too much) force and it will pop (as it is getting on it's track) and move properly then.

 

Note: make sure you are setting the item to push the piston head is in the CENTER of the piston head so it does not damage the piston head. Also, you do not need to push the piston back more than just a half inch, just to make sure it is on it's track.

 

 

If all three of those tests come out working, then your gun should cycle and fire just fine. This will not say it will cycle in full and semi-auto completely properly. If it does not, it is something with the wiring or selector switch.

 

 

Thanks

Dan

[Reincarnation...]

Questions posed by Rattler (Dan)

Hmm.... did you notice a drastic decrease in FPS after any of the upgrades? (specifically the gears or wiring).

Negative. FPS was just fine at the range it was before wiring.

Is it louder after the upgrades, more of a whining sound to it?

Nope, sounds all gearbox I have done and gone. Adjusted the motor height to have that smooth sound when pulled.

The gears could be shimmed badly or timed badly. It could also be a wire not set in the proper position when it was wired to the back and it may be interfiering with the selector area of the gun.

Shimming is good, but I'll check it out again. I believe I timed it right, but please explain more (Used mechbox.com for refference). The wiring of the M4 was like this, front wired gun I used the same thing and rewired to the back, solder on wire extensions of the guage wire, add dean ulta connectors.

How long ago did you perform the upgrades? did YOU personally do the upgrades?

Overall this configuation had been like this for 1 month. Every was upgrade bit then put together, then upgraded more, repeat. Yes I did this myself and know how to do it. I know mp5, m4, m14 (ver 2, and ver 7 well).

It sounds more than anythink else like it is something not coordinated properly rather than a wiring issue, however your answers to the above questions can tell a lot.

 

*Note, if I time my bursts right in full-auto my mechbox doesn't lock up. And I do check my work before putting the mechbox and body together; check my piston and my air nozzle, etc. This is the first time occurance with my 4th m4 personally own and 8th m4 overall.

[Rattler]

I made a typo, where I said had the FPS changed, I meant the ROF. Very sorry about that.

 

 

It seems like you know what you are doing and please dont take anything wrong. I was just curious to see if you had a private person do it, a business or you did it yourself. I like it when people do their own AEG work, it helps them know their weapon better and with that they tend to take better care of their weapons (not saying you dont take care of you gun).

 

 

Also, I very much like your style of answering questions, makes it very easy to read when it is with the question and in red.

 

 

For timing on the gears you want to have the tappet plate catch on the sector gear to be in the 1-2 o-clock position, or at about a 45 degree angle to the right from the top of the gearbox. Mechbox.com does good with their explanation.

 

 

Before taking the gearbox apart, just check and make sure the gears can move freely as described in step one of my above post.

 

 

 

Thanks much,

Dan

[Reincarnation...]

Post by Rattler.

I made a typo, where I said had the FPS changed, I meant the ROF. Very sorry about that.

ROF seems the same, maybe just a little bit more but probably due to a slightly larger battery.

 

It seems like you know what you are doing and please dont take anything wrong. I was just curious to see if you had a private person do it, a business or you did it yourself. I like it when people do their own AEG work, it helps them know their weapon better and with that they tend to take better care of their weapons (not saying you dont take care of you gun).

Same here, why buy a gun with hard earn money and not learn everything about it. Same thing with cars for me.

 

Also, I very much like your style of answering questions, makes it very easy to read when it is with the question and in red.

Thank you. Technically I was to lazy to type out complete sentences

 

For timing on the gears you want to have the tappet plate catch on the sector gear to be in the 1-2 o-clock position, or at about a 45 degree angle to the right from the top of the gearbox. Mechbox.com does good with their explanation.

Timing correctly. I know of that, I remember putting it together and have my anti-reversal latch falling out after every fail attempt to align everything up right and to hold in the spring guide causeing me having to re-time the gears about 4 times that day.

 

Before taking the gearbox apart, just check and make sure the gears can move freely as described in step one of my above post.

Your procedures almost mirrors mine

 

Oh gosh I just notice all the typos and grammer mistakes in my previous post.

[Stealthbomber]

.

If the gears are hard to move and can not move freely, the the gun is shimmed too tight, timed badly or there is a problem with one of the gears (most likely of the three is too tight of shimming).

Gear timing?

 

Personally, I'd suggest pulling the gearbox out of the gun, fitting the grip to the bottom of the gearbox, fitting the motor and then hooking it up to a battery and test-firing it.

 

If there's nothing obvious wrong with the gearbox there's a good chance the problem is because the motor isn't aligned with the gearbox, either due to the grip or the receiver not being quite the correct shape.

[Rattler]

Yes gear timing, that would be an issue as some people place the teeth already in the pistons teeth, thus turning the gears would begin pulling the piston causing it to be hard to turn the gears. That is one result of poor gear timing, it is not very common, but it can be an issue depending on how the gun is re-assembled.

 

 

The reason I take the process I do is to save from damaging any parts, if something is not in proper place and you hit it with the motor, it could damage something inside the gun, and from there on in if you do not take immediate attention to the new problem, you get a chain reaction of parts breaking in the gearbox.

 

 

Once you have determined that the gearbox is working fine by testing it with a screwdriver in the above steps, testing it with the grip on the gearbox with the motor would be a very good idea, a few bodies are too tight on the gearbox which also messes up the select fire feature. However if it is switching from semi to full as you are describing, this does not appear to be the issue, however give it a try and see.

 

 

Sorry if im sounding like an *albartroth* Stealth, that is not my intention in any way, just clarifying myself since I failed to do so earlier.

 

 

Thanks

Dan

[UrPeaceKeeper]

Yes gear timing, that would be an issue as some people place the teeth already in the pistons teeth, thus turning the gears would begin pulling the piston causing it to be hard to turn the gears. That is one result of poor gear timing, it is not very common, but it can be an issue depending on how the gun is re-assembled.

 

Putting the sector gear in engagement with the piston will only affect the gear train ONCE. Either the piston will strip itself out (90% probability) or if it survives, the gears reset and it pulls correctly after that. Gear timing is a myth. Once the first shot is shot from the gearbox (if it the piston somehow survives the first shot) the gearbox resets itself. Then again if you are daft enough to put them in an awkward engagement maybe you shouldnt be putting GB's together.

 

The OP has obviously fired more than 1 shot through his gun in this state which proves it is not "gear timing" because if gear timing was true he would have seriously messed up his gears and piston. No joke! Think about it.

[Stealthbomber]

You can't position the gears so they're meshing with the piston teeth.

The thicker rear tooth on the piston stops you.

[UrPeaceKeeper]

You can't position the gears so they're meshing with the piston teeth.

The thicker rear tooth on the piston stops you.

 

Again if it was possible. But not all gears have thicker last tooths. I know this because my G&P Sector gear has unifrom teeth thicknesses. Also the CA gearset I have here is likewise the same. EVEN if you could it is highly unlikely the piston would survive the first shot. Even if it DID it would not continue to miss pull each time. The only way Gear timing is remotely an issue is if you hvae a high ROF and you your gears spin faster than the piston travels forward. On this gearbox, and any normal gearbox condition this is not an issue, nor would it be one.

[Rattler]

I do not put them in aukward engagements, I always place it at the 45 degree angle (it being the sector gear). Im not sure if that was reference to me or just a general statement.

 

That particular statement quoted was not meant towards "Reincarnation", it was meant as saying immediately after placing the gearbox back together, I run that test to make sure the gears ARE set right so I do NOT strip the piston.

 

The gears do not always stop in the same place (depending on the gun) when a cycle finishes, they stop in a small variance of area, that is why if you look at a gearbox when it is exposed and you fire it, the piston will stop in a different spot every time (in semi-auto this is speaking). Gear timing will NOT eliminate this (this being the variance of stop) COMPLETELY, I just set them to help prevent this as much as I can to try to control the stop variance as much as I can.

 

 

Edit: I think there was a typo or a misunderstanding, stealthbomber means the grab tooth on the piston.

 

I dont put GB's together with the teeth meshing, I have just seen it on guns I have worked on. I THINK they thought proper gear timing was to pull the piston and set the gear in the teeth, holding on the AR latch, idk, don't ask me how they did it. They just said "I upgraded it, pulled the trigger and it pulled a little and now only goes click" and that is what the problem was.

[UrPeaceKeeper]

I do not put them in aukward engagements, I always place it at the 45 degree angle (it being the sector gear). Im not sure if that was reference to me or just a general statement.

 

Nope it was a general statement to all. The placement you speak of is just a good general guide line. You CAN put the teeth in any position so long as they dont engage the piston. I'm kind of thinking we need to bring back Hissing Sid to argue this point =\ Maybe Darklite will throw light in.

[Stealthbomber]

Again if it was possible. But not all gears have thicker last tooths. I know this because my G&P Sector gear has unifrom teeth thicknesses. Also the CA gearset I have here is likewise the same. EVEN if you could it is highly unlikely the piston would survive the first shot. Even if it DID it would not continue to miss pull each time. The only way Gear timing is remotely an issue is if you hvae a high ROF and you your gears spin faster than the piston travels forward. On this gearbox, and any normal gearbox condition this is not an issue, nor would it be one.

Go and re-read my post.

 

PISTON.

 

The PISTON has a thicker tooth at the back.

 

When the piston is forward, try and fit the sector gear so it's meshing with the piston.

Can't be done because the teeth of the sector gear won't mesh with the thicker tooth on the back of the PISTON.

 

Even if you did manage to make the sector gear mesh with the piston, it wouldn't hurt anything. All that'd happen would be that the first shot would be low powered because the piston would be released after only winding part of the way back.

 

 

*EDIT*

In general, the ratio of teeth on the various gears means that there is never any correlation between the positions of the various gears.

People used to set the bevel gear so the anti-reversal was locked before fitting the sector gear to make sure the sector gear always ends up in a position where the bevel gear is locked.

Wrong!

If the overall ratio between the bevel gear was 2:1, 4:1 or 8:1 etc then yes, this'd be useful. They're not. It isn't.

Besides that, the bevel gear spins something like 20-odd times for every revolution of the sector gear so the position of the anti reversal isn't terribly important.

 

As for where the sector gear comes to a halt, that's down to the cut-off cam on the sector gear.

The sector gear rotates until the cut-off cam operates the cut-off lever and disconnect the trigger and the gun stops shooting.

The "timing" of your gears is all built into the sector gear and is predetermined by whoever manufactured the sector gear.

 

Where the gears actually come to a halt after a shot in semi is largely determined by the characteristics of your motor (assuming your aren't using any kind of active braking system).

 

If you're using a motor with weak magnets, such as a TM EG700, the motor will spin down relatively slowly and the gears will continue to spin after the power is disconnected.

When this happens they usually come to a stop when the sector gear engages the piston again.

 

If you use a motor such as the Systema Turbo, which has incredibly strong magnets, the gears will stop much more quickly because they don't possess enough momentum to force the motor shaft to turn.

 

In any case, there's nothing an owner can do (short of fitting an active braking circuit or modifying the cut-off cam on the sector gear) to improve or alter the position the gears end up in after a firing cycle finishes.

[Rattler]

Nope it was a general statement to all. The placement you speak of is just a good general guide line. You CAN put the teeth in any position so long as they dont engage the piston. I'm kind of thinking we need to bring back Hissing Sid to argue this point =\ Maybe Darklite will throw light in.

 

 

Im not trying to create an argument, not at all, I am just stating my info behind my statements. Is it always right? no, so I take all experiences and opportunities to learn.

 

Personally I have been experimenting with gear timing trying to figure it out, I used to think it was a myth but had changed my mind after seing a few gearbox instances (said above).

 

I hope you see and understand what I am saying and see my experiences with gear timing and how I do feel it can be an issue at times.

 

 

 

Thanks

Dan

[UrPeaceKeeper]

Go and re-read my post.

 

PISTON.

 

The PISTON has a thicker tooth at the back.

 

When the piston is forward, try and fit the sector gear so it's meshing with the piston.

Can't be done because the teeth of the sector gear won't mesh with the thicker tooth on the back of the PISTON.

 

Even if you did manage to make the sector gear mesh with the piston, it wouldn't hurt anything. All that'd happen would be that the first shot would be low powered because the piston would be released after only winding part of the way back.

 

Whoops misread that one =\ I blame lack of sleep :runs:

 

Rattler, everyone is entitled to their oppinion I respect that. We should agree to disagree. SB is correct, I mis read his post. True though if you could it would be reduced in FPS, then every shot after that would be normal. I was thinking of the opposite case. Again I blame lack of sleep! (it's been a long weekend)