BB's not firing from TM M1A1

Avenging Angel · November 25th, 2005, 11:42

Yeesh, I just can't win with this gun.

Okay... I just finished installing high speed gears into a ver 6 mechbox. I shimmed it all according to the instructions etc. But, once I re-assembled my TM M1A1, it will not fire BB's. The BB's just get stuck between the nozzle and the hopup mechanism. Originally, I thought that it might be the hop-up so, I took that all apart and rebuilt it. I put the gun back together and tried to fire again and the same thing happened.

Now, I've taken everything but the mechbox apart and I'm trying to figure out what could be causing my problems. I've noticed something that might be having an effect but I'm not sure. If I put my finger near the nozzle, there is a fairly large amount of suction that is taking place before the piston completes its cycle and empties the air. Is this a normal occurance or could this actually be the source of my problems? Anyone have ideas of what else it could be? As a note, there are no other upgrades that have been done to the gun. I've only put in the high speed gears.

Trader rating · November 28th, 2005, 09:21

sounds like a compression problem
if im not correct, the M1A1 has a 3/4 ported cylinder. might be worth seeing if its blocked.

when you fire it, does it push out air? like alot? Its rare, but your piston head's o-ring might be dammaged to the effect that it will seal on the pull back but not the forward push.
If its still pushing air, check to see how the loading nozzel cycles if at all. Im sure the V6 works somewhat the same to V2 and V3 in terms of cycling the tappet plate and nozzel. making sure its timing is correct and that little sping that pulls it forward is still attached might be worth checking.

and if that works fine, turn your hop-up all the way off, spray in some silicone lube and try again.

Mantelope · November 28th, 2005, 09:45

Can you give an exact list of what parts you have in the box? If you've ever relubed the cylinder/piston head, what lube did you use?

concept_8 · November 28th, 2005, 09:50

Never worked on a v6 before, but I had a simple problem once where I didn't seat the nozzle on the tappet plate propperly in the grove it's supposed to sit in, and it casue the nozzle to be pulled back but not be pushed forward and load the bb's propperly.
A simple over site but it cause the gun not to work till I found it so it might be worth a check.
Good luck.

Avenging Angel · November 28th, 2005, 11:46

Well, it's pushing as much air out as it's sucking in which, is a fair amount. When the piston is comming back, it creates a perfect seal. If I put my finger over the nozzle, the piston cannot move because it has no where to suck air in from. Upon examination of the nozzle and tappet plate, neither of those parts are actually moving by the looks of things.

Droc, when you say "making sure its timing is correct and that little sping that pulls it forward is still attached might be worth checking." I don't quite understand what you mean by this. I have a spring that pushes the tappet forward (and that part is attached properly) but as per the "timing" I must say that I'm completely lost. In regards to the gears, there's nothing to time provided that the piston is in the fully rested position. So, how and what do I go about timing?

harleyb - Parts in the mechbox are all stock except for Systema High Speed gears, oiless bushings, and shims.

Whilst trying to fix things, the gearbox snapped my tappet plate in two so I'm dead in the water for a little while. I'm ordering in a polycarb tappet plate so hopefully that will be a little bit more durable.

Mantelope · November 28th, 2005, 14:07

If you used a very heavy lube like lithium grease on the piston head, that might be causing your problems. Degrease the piston head, cylinder head and cylinder as fully as possible, and then try something lighter like silicon oil or Superlube.

Trader rating · November 28th, 2005, 14:30

im not 100% sure how the timing in a V6 works, but it should be similar to the timing in a V2/3
where the tappetplate meets the gears, the gear should have a little nub on it that the tappet plate hits with the gear turnes

in a V2/3 you can see above how the gear has a little nub and how the tappet plate is next to it. the pic above shows proper timing with the nub at 2 o-clock

i cannot seem to find any pics of what the gears in the M1a1 look like, but im sure its close. The tappet plate should have a small spring that connests it to the mechbox shell to pull it forward(and the nub on the gears pulls it back). if your timing is wrong, that would explain why your not firing even with compression.

Avenging Angel · November 28th, 2005, 15:24

Okay, now I understand. I originally had the gear set up in a fashion where the gear teeth started at 3 o'clock and ended and 9o'clock. Everything was was setup according to how THIS pic showed. (Note that the gear setup is shown in that diagram as compared to the pic that you just posted. That's why I did it that way.) The M1A1 and P90 have the same mechbox only with a different motor mounting method so I figured that I could cheat and get a good idea of how everything went together. I'll try resetting the gear and see what happens. My new tappet should be here within the week I think.

Also, when you were talking about the porting, I can't find anything that I would define as a port in the piston housing. It's completely solid. From what I'm gathering from your post, there should be one somewhere on the piston housing. So, my question is, where about should this port be located on the cylinder? When you say 3/4, what does that refer to? (Please forgive the question, I've just never heard of porting in airsoft cylinders before.)

I'm not using a heavy grease at all... in fact, the grease in the piston cylinder is stock. I haven’t touched it. As per the gear grease, I'm using a light grease that I had left over from when I made my last "explorer" robot. If the gearing doesn't work, this will be the next thing to try.

Avenging Angel · December 7th, 2005, 11:46

*UPDATE*

The gun has been fixed. The problem was that the tappet plate was not mating correctly with the nozzle. The nozzle itself was damaged and was apparently not being pushed forward by the tappet plate. I installed a new nozzle along with the poly carb tappet plate and things are working great once again. Thanks for everyones help!

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November 25th, 2005, 11:42	#1
Avenging Angel Trader rating Join Date: Feb 2004 Location: Calgary, AB	BB's not firing from TM M1A1 Yeesh, I just can't win with this gun. Okay... I just finished installing high speed gears into a ver 6 mechbox. I shimmed it all according to the instructions etc. But, once I re-assembled my TM M1A1, it will not fire BB's. The BB's just get stuck between the nozzle and the hopup mechanism. Originally, I thought that it might be the hop-up so, I took that all apart and rebuilt it. I put the gun back together and tried to fire again and the same thing happened. Now, I've taken everything but the mechbox apart and I'm trying to figure out what could be causing my problems. I've noticed something that might be having an effect but I'm not sure. If I put my finger near the nozzle, there is a fairly large amount of suction that is taking place before the piston completes its cycle and empties the air. Is this a normal occurance or could this actually be the source of my problems? Anyone have ideas of what else it could be? As a note, there are no other upgrades that have been done to the gun. I've only put in the high speed gears.

November 28th, 2005, 09:45	#3
Mantelope Scotty aka harleyb Trader rating Join Date: Mar 2004 Location: Toronto, Ontario	Can you give an exact list of what parts you have in the box? If you've ever relubed the cylinder/piston head, what lube did you use? __________________

November 28th, 2005, 09:50	#4
concept_8 Trader rating Join Date: Sep 2004 Location: sudbury Ont.	Never worked on a v6 before, but I had a simple problem once where I didn't seat the nozzle on the tappet plate propperly in the grove it's supposed to sit in, and it casue the nozzle to be pulled back but not be pushed forward and load the bb's propperly. A simple over site but it cause the gun not to work till I found it so it might be worth a check. Good luck. __________________ "Death in the tall grass"

November 28th, 2005, 09:21	#2
Droc Guest Trader rating	sounds like a compression problem if im not correct, the M1A1 has a 3/4 ported cylinder. might be worth seeing if its blocked. when you fire it, does it push out air? like alot? Its rare, but your piston head's o-ring might be dammaged to the effect that it will seal on the pull back but not the forward push. If its still pushing air, check to see how the loading nozzel cycles if at all. Im sure the V6 works somewhat the same to V2 and V3 in terms of cycling the tappet plate and nozzel. making sure its timing is correct and that little sping that pulls it forward is still attached might be worth checking. and if that works fine, turn your hop-up all the way off, spray in some silicone lube and try again.

November 28th, 2005, 11:46	#5
Avenging Angel Trader rating Join Date: Feb 2004 Location: Calgary, AB	Well, it's pushing as much air out as it's sucking in which, is a fair amount. When the piston is comming back, it creates a perfect seal. If I put my finger over the nozzle, the piston cannot move because it has no where to suck air in from. Upon examination of the nozzle and tappet plate, neither of those parts are actually moving by the looks of things. Droc, when you say "making sure its timing is correct and that little sping that pulls it forward is still attached might be worth checking." I don't quite understand what you mean by this. I have a spring that pushes the tappet forward (and that part is attached properly) but as per the "timing" I must say that I'm completely lost. In regards to the gears, there's nothing to time provided that the piston is in the fully rested position. So, how and what do I go about timing? harleyb - Parts in the mechbox are all stock except for Systema High Speed gears, oiless bushings, and shims. Whilst trying to fix things, the gearbox snapped my tappet plate in two so I'm dead in the water for a little while. I'm ordering in a polycarb tappet plate so hopefully that will be a little bit more durable.

November 28th, 2005, 14:07	#6
Mantelope Scotty aka harleyb Trader rating Join Date: Mar 2004 Location: Toronto, Ontario	If you used a very heavy lube like lithium grease on the piston head, that might be causing your problems. Degrease the piston head, cylinder head and cylinder as fully as possible, and then try something lighter like silicon oil or Superlube. __________________

November 28th, 2005, 14:30	#7
Droc Guest Trader rating	im not 100% sure how the timing in a V6 works, but it should be similar to the timing in a V2/3 where the tappetplate meets the gears, the gear should have a little nub on it that the tappet plate hits with the gear turnes in a V2/3 you can see above how the gear has a little nub and how the tappet plate is next to it. the pic above shows proper timing with the nub at 2 o-clock i cannot seem to find any pics of what the gears in the M1a1 look like, but im sure its close. The tappet plate should have a small spring that connests it to the mechbox shell to pull it forward(and the nub on the gears pulls it back). if your timing is wrong, that would explain why your not firing even with compression.

November 28th, 2005, 15:24	#8
Avenging Angel Trader rating Join Date: Feb 2004 Location: Calgary, AB	Okay, now I understand. I originally had the gear set up in a fashion where the gear teeth started at 3 o'clock and ended and 9o'clock. Everything was was setup according to how THIS pic showed. (Note that the gear setup is shown in that diagram as compared to the pic that you just posted. That's why I did it that way.) The M1A1 and P90 have the same mechbox only with a different motor mounting method so I figured that I could cheat and get a good idea of how everything went together. I'll try resetting the gear and see what happens. My new tappet should be here within the week I think. Also, when you were talking about the porting, I can't find anything that I would define as a port in the piston housing. It's completely solid. From what I'm gathering from your post, there should be one somewhere on the piston housing. So, my question is, where about should this port be located on the cylinder? When you say 3/4, what does that refer to? (Please forgive the question, I've just never heard of porting in airsoft cylinders before.) I'm not using a heavy grease at all... in fact, the grease in the piston cylinder is stock. I haven’t touched it. As per the gear grease, I'm using a light grease that I had left over from when I made my last "explorer" robot. If the gearing doesn't work, this will be the next thing to try.

December 7th, 2005, 11:46	#9
Avenging Angel Trader rating Join Date: Feb 2004 Location: Calgary, AB	UPDATE The gun has been fixed. The problem was that the tappet plate was not mating correctly with the nozzle. The nozzle itself was damaged and was apparently not being pushed forward by the tappet plate. I installed a new nozzle along with the poly carb tappet plate and things are working great once again. Thanks for everyones help!

BB's not firing from TM M1A1

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