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SR12 Need Internal Help

SR12 Li-Po gearbox piston piston head spring MOSFET battery wiring internal

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#1 Dmoney Schmidt

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Posted 23 December 2012 - 03:11 PM

Man I haven't been on here in forever! Lol Well anyways I've got a bone stock SR12. I'm running a huge Li-Po, so upgrades will be necessary. The battery I'm using is a Venom 11.1v 4000mAh 20c Li-Po w/ the large type universal connector (with multiple adapters for Deans, Tamiya, etc.). I know a MOSFET is a necessity. I was looking at Extreme Fire. The gun has 1500 rounds through it at most. I do have an occasional issue where I get multiple shots on semi. I've been told this has to do with the trigger contacts and a weak spring/worn parts issues. In the manual it says to dry fire it for 20 seconds. I didn't do it 20 seconds but maybe like 10, and it solved it. If I've already burned up my contacts, are there replacements? So with new wiring, Deans, and a MOSFET, I wanna make the GB more bulletproof. IMO the gears are very strong, and the shell, bearings, and contacts are nice as well. I'm happy with the performance. Are they're any pistons or piston heads that are stronger? Would a new spring help? Is the motor ok with that big of a battery? I'm by no means gonna work on this by myself. I'll take it to a shop. I have a local one with good techs. I just need some understanding as to why this is happening, how it can be solved, and what I can do to strengthen my gearbox. Thanks and cheers!

#2 gcw360

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Posted 23 December 2012 - 07:58 PM

View PostDmoney Schmidt, on 23 December 2012 - 03:11 PM, said:

Man I haven't been on here in forever! Lol Well anyways I've got a bone stock SR12. I'm running a huge Li-Po, so upgrades will be necessary. The battery I'm using is a Venom 11.1v 4000mAh 20c Li-Po w/ the large type universal connector (with multiple adapters for Deans, Tamiya, etc.). I know a MOSFET is a necessity. I was looking at Extreme Fire. The gun has 1500 rounds through it at most. I do have an occasional issue where I get multiple shots on semi. I've been told this has to do with the trigger contacts and a weak spring/worn parts issues. In the manual it says to dry fire it for 20 seconds. I didn't do it 20 seconds but maybe like 10, and it solved it. If I've already burned up my contacts, are there replacements? So with new wiring, Deans, and a MOSFET, I wanna make the GB more bulletproof. IMO the gears are very strong, and the shell, bearings, and contacts are nice as well. I'm happy with the performance. Are they're any pistons or piston heads that are stronger? Would a new spring help? Is the motor ok with that big of a battery? I'm by no means gonna work on this by myself. I'll take it to a shop. I have a local one with good techs. I just need some understanding as to why this is happening, how it can be solved, and what I can do to strengthen my gearbox. Thanks and cheers!
I'll give this a shot...If I miss something let me know.  1500 rounds? The gun's parts are not yet worn in let a lone worn out. The spring shouldn't be weak. And if you are using a stock motor the only reason to get a double shot in semi, assuming nothing is broken, is either a very fast, light, trigger pull which causes the timing to be off, or the battery that is too far out of spec.  Now, based on the post, it's you battery. If you put in a FET with active breaking this will resolve itself.  Again, with only 1500 rounds through the gun the trigger contacts, and everything else, should be fine.  I wouldn't go changing things until they actually break.

Regarding replacement parts / upgrades...The piston head is solid aluminum, they don't break under normal conditions.  The spring should be fine assuming it's shooting in the FPS range you want. Leave the piston alone until it wears out.  Most after market pistons are not any better.  

Lastly, and I meant to put this in the first time, you really should use an in spec battery (15C 1400-1600 mAh).  This should eliminate your issues.
Hope this helps.

#3 vanevery

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Posted 23 December 2012 - 10:23 PM

Your over-all question is quite broad.
What specifically are your performance goals?

I can see that you have the right idea about your battery and a mosfet and to ask the question on the stock motor. If you are using the Li-po you mentioned in your OP with your stock gearbox , your gearbox components will not last long. That battery is not only out of spec for the stock electrical system, but for the stock components as well. You might get away with it if you stay in semi-auto only. but if you are doing full mag dumps in one trigger pull, forget about it. Pro Shop does have trigger contacts if you need to replace them. I have ordered some before from them.
I suggest an after-market motor with your high amp Li-po, but your KWA stock motor should be able to handle it.

Without knowing your specific performance goals, I do always suggest this:
- AOE Correction.
- Add Sorbo
- Radius the Cylinder Windows
- Shim
- New #14 Danco O-ring / or X-ring
- Thorough cleaning of all your gearbox components - especially Cylinder, Cylinder Nozzle, and Air Nozzle
- SuperLube for gears and lower gearbox shell / 30wt silicone oil for piston rails, cylinder walls, O-ring
- Thoroughly clean your inner barrel, bucking, and hop-up unit.

Edited by vanevery, 23 December 2012 - 10:26 PM.


#4 Dmoney Schmidt

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Posted 24 December 2012 - 01:56 PM

I'm happy with the performance. I know this is WAYYYY out of spec, but I got it at an RC store, so that was the smallest they had apparently. I wasn't going to put some 60c monster pack, but the mAh didn't concern me too much. I wanted new wiring anyways to help with the installation of that very large battery. So according to y'all, the motor, piston, and piston head are ok? Just a MOSFET and some new wiring would be ok. And a few touch-ups like Sorbo and what not? Thanks for the help!
P.S. I don't do long trigger pulls. At most 2-5 seconds. Don't wanna mess up my internals.

Edited by Dmoney Schmidt, 24 December 2012 - 02:00 PM.






Also tagged with one or more of these keywords: SR12, Li-Po, gearbox, piston, piston head, spring, MOSFET, battery, wiring, internal

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