Upgrade/Service my KA M4A1 - What to do...?

.K.A.L.I.M.A.

As the title states, I want to upgrade / service my King Arms M4A1. I'm planning to head down to Tigerland in a few days and I just want to have the AEG ready, and not letting me down on the day, as it's been over a year and four months since I last went down.

Bought the M4A1 back in September from the lads at AirsoftEire, and it hasn't really seen much use, roughly 4'000 BB's.

So far, this is what I've done (In order):
- New cut-off lever (SEMI started to fire AUTO, so i got a SHS).
- New wiring (Had to cut the standard to get inside the AEG).
- New Madbull Blue and Element H-Nub (Roughly getting 40m - 45m straight with no wind. Both only seen roughly 1'000 BB's).

I know my way through a V2 gearbox. Is there any simple mods to improve air seal, accuracy/range, etc... Should I clean and regrease my gearbox (Use Lithium grease?)? Should I change a part?

Any help is appreciated. Thank you.

Untamedlemon

.K.A.L.I.M.A. wrote: »

As the title states, I want to upgrade / service my King Arms M4A1. I'm planning to head down to Tigerland in a few days and I just want to have the AEG ready, and not letting me down on the day, as it's been over a year and four months since I last went down.

Bought the M4A1 back in September from the lads at AirsoftEire, and it hasn't really seen much use, roughly 4'000 BB's.

So far, this is what I've done (In order):
- New cut-off lever (SEMI started to fire AUTO, so i got a SHS).
- New wiring (Had to cut the standard to get inside the AEG).
- New Madbull Blue and Element H-Nub (Roughly getting 40m - 45m straight with no wind. Both only seen roughly 1'000 BB's).

I know my way through a V2 gearbox. Is there any simple mods to improve air seal, accuracy/range, etc... Should I clean and regrease my gearbox (Use Lithium grease?)? Should I change a part?

Any help is appreciated. Thank you.

What do you want your gun to be able to do. Ie. high speed, high torque bit of both etc.? Then we can narrow it down

.K.A.L.I.M.A.

Untamedlemon wrote: »

What do you want your gun to be able to do. Ie. high speed, high torque bit of both etc.? Then we can narrow it down

I ain't looking for any high speed setup for the AEG. I find that the motor in it is perfect enough, so I'm going to leave it in there for a long time. However, I'm planning to get around the 320fps mark with 0.25g BB's. Any suggestions there?

.K.A.L.I.M.A.

Forgot to mention as well, soon enough I'll be running my AEG on a 4'000mAH/5'000mAH 9.6V battery rear wired.

Southern Dandy

.K.A.L.I.M.A. wrote: »

I ain't looking for any high speed setup for the AEG. I find that the motor in it is perfect enough, so I'm going to leave it in there for a long time. However, I'm planning to get around the 320fps mark with 0.25g BB's. Any suggestions there?

Well firing at 320 with .25g bb's will put you over the legal limit I think with .20g making your aeg a illegal.

As for maintenance get new O-rings for your piston head, grease this sparingly with silicone grease, next use silicone oil on the inside of your cylinder again do not use a whole lot.

Firstly strip the lot down and clean the gearbox shell.

Coat your cylinder head O-rings again with a little silicone grease. Also apply a small bit on the nozzle that you air nozzle slips over.

Then perform your compression test.

As for the gears I use castrol LM grease, you don't need to lather it and make them swim in the stuff only a thin layer. I also put a small bit on the gear shafts aswell.

I normally then put a little grease on the little tracks that the rails on your piston slip into.

I use a mosfet in my aegs so my trigger contacts don't need a little rub down. Your might depending.

I'd also clean your inner barrel, hop up chamber and Hop up rubber while your at it.

You can also buy ASG brand maintenance stuff on the net but can be pricey. I think you mentioned lithium grease as well but what I have read before is lithium and plastic does not go well together (apparently) and is not overly suited to gears. I'll try and pull up that article is I can find it.

Anyways hope this helps, let me know if I forgot something.

Southern Dandy

.K.A.L.I.M.A. wrote: »

I ain't looking for any high speed setup for the AEG. I find that the motor in it is perfect enough, so I'm going to leave it in there for a long time. However, I'm planning to get around the 320fps mark with 0.25g BB's. Any suggestions there?

Well firing at 320 with .25g bb's will put you over the legal limit I think with .20g making your aeg a illegal.

Firstly strip the lot down and clean the gearbox shell.

As for maintenance get new O-rings for your piston head, grease this sparingly with silicone grease, next use silicone oilon the inside of your cylinder again do not use a whole lot.

Coat your cylinder head O-rings again with a little silicone grease. Also apply a small bit on the nozzle that you air nozzle slips over.

Then perform your compression test.

As for the gears I use castrol LM grease, you don't need to lather it and make them swim in the stuff only a thin layer. I also put a small bit on the gear shafts aswell.

I normally then put a little grease on the little tracks that the rails on your piston slip into.

I use a mosfet in my aegs so my trigger contacts don't need a little rub down. Your might depending.

I'd also clean your inner barrel, hop up chamber and Hop up rubber while your at it.

You can also buy ASG brand maintenance stuff on the net but can be pricey. I think you mentioned lithium grease as well but what I have read before is lithium and plastic does not go well together (apparently) and is not overly suited to gears. I'll try and pull up that article if I can find it.

I should also say that the lithium grease I am on about is that spray stuff in a can think it blue and drys quite quickly, castrol LM grease is lithium based, comes in a tub and often used in wheel bearings etc on cars.

Anyways hope this helps, let me know if I forgot something.

Untamedlemon

I like to put in a full metal tooth piston ( the shs one from hobby is quite good) because I find that they last wayyyy longer than your standard piston. You could also put in a metal bearing spring guide because from my knowledge those kA ones come with a plastic shaft.
Just a few suggestions

DeBurca

If it aint broke dont fix it KA gearboxes are pretty good stock
I would leave it as is for now unless you have issues with it or a loss of FPS then and only then would I bother doing any work to the box

If you are having issues or you just plain want to go in then follow the advice in Southern Dandys post
Personally I am not a big fan of all metal toothed pistons as they are both noisy and if/when things go wrong they have a habit of going and taking the gearset with them

PS 320fps with .25g BB equals 1.18 joules

Untamedlemon

DeBurca wrote: »

If it aint broke dont fix it KA gearboxes are pretty good stock
I would leave it as is for now unless you have issues with it or a loss of FPS then and only then would I bother doing any work to the box

If you are having issues or you just plain want to go in then follow the advice in Southern Dandys post
Personally I am not a big fan of all metal toothed pistons as they are both noisy and if/when things go wrong they have a habit of going and taking the gearset with them

PS 320fps with .25g BB equals 1.18 joules

As deburca said ^ metal toothed pistons can be noisy but if you shim your gears perfectly and correct the angle of engagement then it shouldnt be all that noisy.
Also what I said was for improvements and aren't actually necessary. I like to put them in , that doesn't mean that everybody does.
Just some suggestions

.K.A.L.I.M.A.

Thank for the help guys. Actually looks like I'll be heading down this Saturday (In a couple of hours, to be exact :pac:)

So all I should use is silicone grease and oil, as well as the Castrol LM grease. As for the lithium grease that I mentioned, it wasn't in a can but in a tube.

I was considering putting in a full metal tooth piston, but would that wear the sector gear more? The KA gearbox does come with a plastic spring guide, so that's one thing I do want to change.

As for the FPS, what spring should I use? I'll be mainly using .25g BB's in my AEG.

Untamedlemon

.K.A.L.I.M.A. wrote: »

Thank for the help guys. Actually looks like I'll be heading down this Saturday (In a couple of hours, to be exact :pac:)

So all I should use is silicone grease and oil, as well as the Castrol LM grease. As for the lithium grease that I mentioned, it wasn't in a can but in a tube.

I was considering putting in a full metal tooth piston, but would that wear the sector gear more? The KA gearbox does come with a plastic spring guide, so that's one thing I do want to change.

As for the FPS, what spring should I use? I'll be mainly using .25g BB's in my AEG.

To use a full metal tooth piston effectively you really need to shim you gears perfectly and correct the angle of engagement otherwise, as you said, youll just destroy your gear in no time and your gearbox will be realllllllly noisy as DeBurca said ^^.
As for the spring you really have to use an m90 unless you have a bad air seal. Honestly I wouldn't change the spring in a KA unless it breaks because they're quite good

DeBurca

You need a spring that produces an energy output of equal to or less than 1 joule
It is the spring alone that determines the total muzzle energy of your AEG

As to what weight BB you decide to use the spring does not know or care, all you need to ensure is that the spring produces an energy output of equal to or less than 1 joule in order to conform to Irish law
Yes a .25g BB will exit the barrel slower than a .2g BB but the total energy of the two BB will still be the same as they exit the barrel
Both are subjected to the same external forces (wind resistance and gravity etc) but at 20-30 meters although both have slowed the retained energy of the heavier BB will be greater and will be less effected by any type of cross/head wind etc

1 joule = 328fps/.20g BB
1 joule = 305fps/.23g BB
1 joule = 293fps/.25g BB

.K.A.L.I.M.A.

Down at Tigerland today and I got the AEG chronoed. It came in at 239-245 FPS with King Arms 0.25g BB's, which I was sort of disappointed, so I definitely want to change the spring and the spring guide, maybe even rewire to the stock while I'm at it.

Does anyone have good recommendations for a spring? ULTIMATE, etc..... And what sort? M90 or M95, etc...

Thank you.

Shimming - I didn't go near the shimming yet in the gearbox, and I find that it's perfect the way it is. I tried moving the gears but they didn't budge. Should I still do something about it?

Also, what is "Angle of Engagement"?

Untamedlemon

.K.A.L.I.M.A. wrote: »

Down at Tigerland today and I got the AEG chronoed. It came in at 239-245 FPS with King Arms 0.25g BB's, which I was sort of disappointed, so I definitely want to change the spring and the spring guide, maybe even rewire to the stock while I'm at it.

Does anyone have good recommendations for a spring? ULTIMATE, etc..... And what sort? M90 or M95, etc...

Thank you.

Shimming - I didn't go near the shimming yet in the gearbox, and I find that it's perfect the way it is. I tried moving the gears but they didn't budge. Should I still do something about it?

Also, what is "Angle of Engagement"?

Ultimate m90 springs are pretty good and they should bring your gun down to ~300-310fps which is usually what people aim for so that there is less of a chance of 'firing hot'.
As for shimming, if you want to put a full metal tooth piston in then your shimming needs to be perfect or else it'll cause an absolute racket. It might seem perfect and KA are pretty good but it's rare that youd get a perfectly shimmed 'stock' aeg.
Angle of engagement is the angle in which your sector gear makes contact with the last tooth on your piston. Ideally whatever angle the tooth on your sector gear is then the last tooth on your piston should be going at the same angle. Usually aeg's don't come with the aoe corrected. What you can do is fit Sorbo pads to the part of your cylinder head that the piston contacts. You keep adding pads until your piston reaches the correct position. You'd be better looking this up on YouTube because you'd understand it better if you can visually see it
Btw if your going to rewire it get the ultimate silver wiring. It costs like €13 in airsofteire but it's really good stuff I can't recommend it enough. Also get deans if you don't already have Them.

I thought you said 340 and not 240( should've gone to specsavers!!). Anyway what southern dandy said below is correct, you definitely have an airleak. Open up your gearbox as soon as possible and make sure all the o rings are intact. Use a tiny bit of silicon oil on them and rub it in, and I mean a tiny bit. After that check your air nozzle for cracks, your hop rubber etc. Make sure that no air can escape.
Sorry for the error there.

Southern Dandy

Going by your fps I'd be thinking you have a nice airleak, the maintenance I mentioned above will make a significant jump. I'd do this before you buy a spring.

I have a ultimate M100 in my KWA, with a type 1 ported cylinder giving me 315fps approx.

Shimming can take a bit of practice to get it right. But it will prolong your gears lifespan and make your aeg quieter.

I'd get a bearing spring guide provided you do not have a bearing piston head.

You can order 40D sorbo pads an low res wiring from air-labs.co.uk. Nice and cheap and the website has installation tutorials. The cable is excellent quality and comes in various sizes 14, 16, 18 awg.

.K.A.L.I.M.A.

Well I'm sorted on the wiring, but I'm just curious are G&P T-Shape Connectors a good choice? Also, since my inner barrel is 363mm, will a Type C/3 cylinder work?

Inari

G&P Deans/T connectors are a damn sight better than tamiya connectors, but are not necessarily the best deans connector available.

Type C cylinder is perfect for a 363mm barrel - it'll do up to a 400mm barrel if memory serves. More than enough volume for you