L85 Piston Issues

SentinelStance

Messing around with an ARMY L85's gearbox and encountered a problem:it is taking six to seven trigger pulls for the piston to complete its cycle.
Can anyone think of a reason as to why this is happening? I am a novice to this type of thing. I should mention the gearbox is using a standard piston with a spacer and a standard gearset, not the elongated SR25 style one. Could this be part of the problem?

Untamedlemon

SentinelStance wrote: »

Messing around with an ARMY L85's gearbox and encountered a problem:it is taking six to seven trigger pulls for the piston to complete its cycle.
Can anyone think of a reason as to why this is happening? I am a novice to this type of thing. I should mention the gearbox is using a standard piston with a spacer and a standard gearset, not the elongated SR25 style one. Could this be part of the problem?

I'm almost certain that l85's use a 19 tooth piston and not the standard 15 tooth so that ight be your problem.

SentinelStance

Yes. Which is why I am using a spacer with standard piston and gearset to fill the gap.

Untamedlemon

SentinelStance wrote: »

Yes. Which is why I am using a spacer with standard piston and gearset to fill the gap.

I'm not overly familiar with l85 gearboxes but I'm not sure if that would work properly or not maybe talk to just a pinker because I think he has an l85.

SentinelStance

Untamedlemon wrote: »

I'm not overly familiar with l85 gearboxes but I'm not sure if that would work properly or not maybe talk to just a pinker because I think he has an l85.

Thanks. That was helpful.

Inari

SentinelStance wrote: »

Thanks. That was helpful.

Yes, because being sarcastic is the way to encourage people to help you.

Anyway, it sounds like a problem in current transfer, so your usual suspects are:
- Battery (Simple to test; use a different battery - preferably higher voltage & fully charged)
- Motor (Again, simple to test; connect the motor outside of gun and see if it spins when pulling the trigger, or whether it is laboured - if it's laboured it could be trigger contacts. You can also test with a different motor to eliminate it as a variable)
- Trigger contacts (if they're blackened, burned out i.e. piece missing, or too far apart, then the current will not transfer smoothly to the motor, and your gun will not cycle)

I would also check that your shimming is not too tight. Also, I assume the gun acts the same in full auto as well as semi?

SentinelStance

I know, I understand the guy is trying to help but if your clueless about something whats the point in offering advice? Its a waste of my time.

Its the trigger contacts anyway. Had a look there and they are not in good shape! Are there specific contacts that have to be used or could I knock a new set to together? I have some silver bits off an old battery I am thinking of using or would they be unsuitable?

Untamedlemon

SentinelStance wrote: »

I know, I understand the guy is trying to help but if your clueless about something whats the point in offering advice? Its a waste of my time.

Its the trigger contacts anyway. Had a look there and they are not in good shape! Are there specific contacts that have to be used or could I knock a new set to together? I have some silver bits off an old battery I am thinking of using or would they be unsuitable?

Since you mentioned the piston I thought you might have noticed something with the piston wasn't right......it was just a suggestion of what I do know about l85 gearboxes. I was wrong, that's that, no need to continue.
Sorry.

Inari

SentinelStance wrote: »

I know, I understand the guy is trying to help but if your clueless about something whats the point in offering advice? Its a waste of my time.

Its the trigger contacts anyway. Had a look there and they are not in good shape! Are there specific contacts that have to be used or could I knock a new set to together? I have some silver bits off an old battery I am thinking of using or would they be unsuitable?

Look, I can understand the frustration - but if people are afraid to post in fear of being berated for not knowing enough, then where is their encouragement to offer up what they do know, and potentially help? Also by being wrong, you learn far more than being right. So it is always worth people having a go - no shame in being wrong as long as you can admit it, which he has. So where's the problem

Anyway, provided your switch harness is in good shape, you can of course knock together a set of contacts. You can use pretty much any metal you want - obviously the more conductive it is, the better the results will be. Just make sure the surface is clean (use electrical contact cleaner), and smooth - you don't want the trolley binding when it's all put together.

Untamedlemon wrote: »

Since you mentioned the piston I thought you might have noticed something with the piston wasn't right......it was just a suggestion of what I do know about l85 gearboxes. I was wrong, that's that, no need to continue.
Sorry.

And you were dead right to do so. Regardless of what people may think, if people are discouraged from posting then this place will die a death, and no one will be in a position to help anyone. People will just say "What's the point?" and when questions aren't being answered, people will stop asking. If you go back and read some of my early posts you will see some of the most idiotic questions, and suggestions...but hey, that's how I learned

SentinelStance

Thanks for the help!

jimeryan22

Its the switch lads defo... Prob from manufacturer.. Vid on YouTube showing how to fix.. Called "l85 trigger fix". Did it, worked.. But as I've found out and am in process of doing, Need new switch (contacts pretty ruff from the arking) And install MOSFET to prevent in future