Solving the R85 Piston Problem

[Liam1992]

I can see myself becoming quite a regular Topic starter for the next month or so. Not in vain however, and once its all sorted and I'm up and running I'll pipe down a bit.

So, to todays question. The R85 Piston problem. I am aware they are renowned for stripping pistons even with the blowback disabled (Which it is)

Therefore, I believe (And this is where the question, confirmation comes in), I need the Piston spacer shown below.

http://www.airsoftworld.net/piston-spacer-for-army-armament-r85.html

And in that description is says I need a TM Sector gear, so I googled it, and came up with this!

http://specialairsoftsupplies.co.uk/index.php?route=product/product&product_id=850

So, firstly, am I correct? (Please please say I'm right), and secondly, is it easy to fit? (Ie: Could I do it myself/ is there any online run through's, instructions or such likes.

Cheers in advance Gents, she's going to fire like a beauty once I've emptied my bank account into her!

 

[Airsoft-Ed]

I would say that you are correct on both counts with regard to the parts being what you think they are.

However, I'd be more likely to question how you came about learning that you need a special piston and specific sector gear, as opposed to checking whether the parts are right.

I can understand the piston being important because the standard one is "proprietary" with the exception of this custom one. But the sector gear thing seems strange, because I'd have thought that all sector gears were the same... And if the sector gear needs to be changed, it suggests that the standard one is irregular as well, which makes sense because the piston is unique, but if that's the case, why wouldn't you have to change the entire gear set...?

Hopefully that makes sense to you.

I'd get RR01 to answer it for you, he's exceptionally well versed with the Army Armament L85s, having owned 3 or more... For some reason.

Drop him a PM or draw his attention to this thread, I wouldn't want to tell you you're right without being sure. Though I'm fairly certain those parts can only be the right ones if they're definitely what you're looking for.

As for doing it yourself, I think most people will get by. So long as you have a fairly intuitive understanding of basic mechanical things and basic knowledge of electronic circuitry you ought to be completely fine. It's more a pain in the arse than complicated lol.

But if you're the kind of person that can't understand how the mechanics of say, a wind up car, or something like that work, then steer clear until you've watched some video guides and read around a bit etc.

If you're worried you might screw it up and it's going to be a long term project, then you could buy a super cheap, crappy, dead gun and try and make it work, to get some practice in. Buying broken and trying to fix for as cheap as possible is actually a fairly good way to practice, you could potentially turn a profit by selling them on afterwards as well.

 

[Deva]

Don't purchase anything from the 2nd link.

http://www.airsoft-forums.co.uk/index.php/topic/1248-special-airsoft-supplies-a-terrible-experiance/

A quick Google will reveal more too.

You have been warned

 

[Liam1992]

In all honesty it is just from reading around the subject.

This is a quote from the first link off of Airsoft World:

"Please be aware though, you NEED to replace the sector gear with a standard TM type gear to deal with the lesser tooth count. If you don't feel up to that task, we offer an all-in package including the spacer, piston, gear, fitting & collection & return postage"

I understand they are a reputable company and kind of took that as Gospel, I shall send RR01 a quick message, would rather go from someone with a good experience than just what I've read here and there.

Thanks for the heads up on that website, disappointing however, as there price on a box of 10 set of Magpul PMag 75rd Magazines was excellent, will steer clear by the sounds of it!

Cheers,

Liam

 

[Airsoft-Ed]

Airsoft World are definitely reputable, probably one of the most reputable companies in fact. You can probably get a sector gear from them as well, saves you paying for postage twice and you can avoid using the site with a bad rep.

RR01 ought to set you straight for definite though. Good luck with it.

 

[Liam1992]

Sent a message over to RR01, hoping a bit of wisdom will see me right!

My initial R85 purchase was from Airsoft World as it happens, and I remember the delivery being rapid then as well.

 

[RR01]

PM replied to.

 

[Deva]

If there is anything particularly useful in your PMs, is there any chance it could be posted back up here? It'll likely benefit others.

Thanks

 

[Liam1992]

Hi Liam,

OK, the ARMY R85 can crack the rear off of the piston. I had it happen to the first one I bought second-hand, but I think it was more due to lack of maintenance and a poorly set up gearbox than anything inherently wrong with the piston. Part of the problem may be due to the way the R85 is set up on semi to hold the piston in the cocked position, although that said it really should not have that effect, as all the strain is then placed on the front part of the cogs on the piston. It could also be piston bounce, or the Angle of Engagement being slightly off if the wrong piston head is used. I had this on a non-working R85 which I bought off of a fairly knowledgeable guy on another forum. He couldn't get it to work, but as I had a couple of fully working ones to compare to I could see someone had fitted a new piston head that was the wrong depth, so the first tooth on the Sector gear was missing the back of the piston completely. It was lucky that one didn't crack off the rear of the piston as well, but I have a spare anyway.

If you change to a standard piston with the spacer included then you also need to change the Sector gear, at minimum, since the standard R85 gearbox uses a 19 tooth Sector gear / piston combination, whereas standard V2/V3 gearboxes use either a 15 or 16 tooth gear / piston combo. This also means you lose the pre-cock function on semi and as the R85 isn't the fastest cycling gearbox it takes a little longer to get off that first shot in semi. If you change the Sector gear then personally I'd put a whole new gear set in there and probably new bushes as well. The cost then mounts up, so you're probably already at £50-£60 for all the components.

As regards repairs, the ARMY R85 gearbox is just about one of the easiest to work on, similar to the ICS gearboxes, in that the cylinder / piston part is a separate component and comes off with just the pull of a single pin once the upper & lower receivers are split, then 4 small cross-head screws split the casing. Last time out with my L85A2RIS I had a drop off in fps half way through the day. A quick run back to the safe zone, a small cross head screwdriver and five minutes had it all back together and power restored. There's not that many AEGs you can do that to.

ARMY R85s are clones of the G&G L85. So far as I can tell, ALL the G&G L85A1 parts fit and are available direct from G&G if nobody in the UK or Hong Kong has them in stock. Just don't mention you are buying for an ARMY gun, although I think when they first came out the ARMY literature suggested getting spares from G&G. E-mail address is: [email protected]. They also have exploded drawings on their website: http://www.guay2.com.../gb/L85-box.pdf andhttp://www.guay2.com...s/l85/L85A1.pdf

Personally, I use my L85s mostly in semi, partly because I use midcaps, but also because I find it more accurate. Even if you go for the shorter piston / extender option you don't lose Semi, it's just then as most other AEGs in that the piston starts at rest, moves all the way to the back, then is released to shoot. The ARMY L85 does away with that by keeping the piston at the rear between shots, so effectively BANG, RE-COCK, instead of RE-COCK, BANG as with say an M4.

As regards G&G, you need to e-mail the Support Team and tell them what you want. It's best to locate the part number from the exploded drawings, then tell Support the part number and, for safety, the part name if you know it in your e-mail request. They'll give you a price, including carriage. You tell them to OK the order, giving your Paypal account name. You'll then get an e-mail from Paypal asking you to confirm the funds request from G&G. Accept and agree the funds and your parts will usually be sent within a couple of days. Most of mine arrived within 3 days from being sent, without any customs charges, although if you are ordering a large amount then that can incur their displeasure and the dreaded import charge. Either way it's usually still cheaper than if you source from the UK.

Oh, by the way. If you use it on semi regularly, remember to release the spring tension by pushing on the silver lever in the top of the magwell, to release the anti-reversal latch before you pack it away, otherwise the spring will "set" and lose tension, lowering your FPS.

-----

That is the sum of the two messages from RR01, massively insightful for me, so hopefully will be for anyone else too.

Cheers,

Liam

 

[ginger colin]

Hi... as above....

If you have not done it yet they I would also recommend

Re solder all the joints... Mine were cack, I had a dry joint and it was the cause of many problems

From standard the Army pistons are terrible, they remind me of a kit cyber gun made about 10 years ago.

The first test for a piston is can you dig your thumb nail in to it..... does it leave a mark.... way too soft

I have tried just about every brand and for durablity if you are shooting 328 I love using the standard marui one.

For the last 3 years I have been using the old classic army yellow pistons. I grabbed a shit load on

recommendation just before they changed them.

While the gun is apart drop a Classic army sr25 tappet plate in

If you are on a budget then you can simply file the extra teeth off your original gear. The gears that it comes

with are actually pretty good quality and run with not too much noise.

If you are running fast, dont forget to dremmel the 2nd tooth off...