Supporters Rogerborg Posted August 2 Supporters Share Posted August 2 1 hour ago, ak2m4 said: @Pollynator_bravo2 clean that inner barrel and wash that rubber We have to maintain our toys? ak2m4, Lozart and gavinkempsell 3 Link to comment Share on other sites More sharing options...
Dan Robinson Posted August 2 Share Posted August 2 16 minutes ago, Rogerborg said: We have to maintain our toys? Never was a character so true to life. [father of a 15 year old] Rogerborg 1 Link to comment Share on other sites More sharing options...
Pollynator_bravo2 Posted August 2 Author Share Posted August 2 6 hours ago, ak2m4 said: @Pollynator_bravo2 clean that inner barrel and wash that rubber Yeah fair point. Not done anything to it since I brought it off a seller. I think it was thrown together with bits from the Airsoft fair Link to comment Share on other sites More sharing options...
Pollynator_bravo2 Posted August 3 Author Share Posted August 3 On 02/08/2024 at 09:38, Lozart said: Timing does indeed mean the cycle of retracting the nozzle to allow the bb into the hop unit, then allowing it forward to seat the BB into the hop before the piston comes forward. If you're not getting a feeding issue that should be OK but if the nozzle isn't actually seating on the feed lips of the hop rubber properly you may be getting an air leak. The chamfered tip of the nozzle should seal into the end of the hop rubber (the feed lip if you will). An easy test is to reassemble the gun, turn it upside down and place a small piece of paper over the feed tube. When you fire the gun the paper should move only minimally, if it blows off then there is air escaping down the feed tube. Also - it may be the camera angle but your barrel doen't look straight in your hop unit - it may need twisting slightly to line it up. So the paper moved a fair bit so I’m guessing air is escaping 🤦♂️ IMG_3676.mov Rogerborg 1 Link to comment Share on other sites More sharing options...
Supporters Lozart Posted August 5 Supporters Share Posted August 5 On 03/08/2024 at 11:59, Pollynator_bravo2 said: So the paper moved a fair bit so I’m guessing air is escaping 🤦♂️ IMG_3676.mov 10.52 MB · 8 downloads We have a winner! Tip of the nozzle isn't sealing with the rubber. Rogerborg 1 Link to comment Share on other sites More sharing options...
Colin Allen Posted August 5 Share Posted August 5 On 03/08/2024 at 11:59, Pollynator_bravo2 said: So the paper moved a fair bit so I’m guessing air is escaping 🤦♂️ IMG_3676.mov 10.52 MB · 10 downloads The nozzle is not fully engaging with the hop rubber lips. Is the hop unit pushed fully back against the gearbox? If it isn't, use some O rings in front of it to push it back. If it is, try longer nozzles or get a variable nozzle. Link to comment Share on other sites More sharing options...
Pollynator_bravo2 Posted August 5 Author Share Posted August 5 3 hours ago, Colin Allen said: The nozzle is not fully engaging with the hop rubber lips. Is the hop unit pushed fully back against the gearbox? If it isn't, use some O rings in front of it to push it back. If it is, try longer nozzles or get a variable nozzle. It’s a weird one as I grabbed the old gear box that came out of it and serviced it fully. When I opened it up the tappet plate looked different. It has a moon shape on the tail end and there is a delay chip however the nozzle is shorter than what I had in the eon gb. When I fitted it all back together (with a clean inner barrel and bucking) I got 335 fps and 1.28j (no hop applied) 🤦♂️🤷🏻♂️ I guess this is an easier problem to fix the the latter lol images are of the gb that came with the gun when I brought it 2nd hand Link to comment Share on other sites More sharing options...
Colin Allen Posted August 5 Share Posted August 5 51 minutes ago, Pollynator_bravo2 said: It’s a weird one as I grabbed the old gear box that came out of it and serviced it fully. When I opened it up the tappet plate looked different. It has a moon shape on the tail end and there is a delay chip however the nozzle is shorter than what I had in the eon gb. When I fitted it all back together (with a clean inner barrel and bucking) I got 335 fps and 1.28j (no hop applied) 🤦♂️🤷🏻♂️ I guess this is an easier problem to fix the the latter lol images are of the gb that came with the gun when I brought it 2nd hand That seems to be the best way forward. I have never seen a tappet plate like that before. Link to comment Share on other sites More sharing options...
Supporters Lozart Posted August 6 Supporters Share Posted August 6 13 hours ago, Pollynator_bravo2 said: It’s a weird one as I grabbed the old gear box that came out of it and serviced it fully. When I opened it up the tappet plate looked different. It has a moon shape on the tail end and there is a delay chip however the nozzle is shorter than what I had in the eon gb. When I fitted it all back together (with a clean inner barrel and bucking) I got 335 fps and 1.28j (no hop applied) 🤦♂️🤷🏻♂️ I guess this is an easier problem to fix the the latter lol images are of the gb that came with the gun when I brought it 2nd hand Wow, that is OLD! The different design of tappet plate would certainly account for what you're seeing. The fix will still be a longer nozzle though as you can't get tappet plates like that any more. Colin Allen and ak2m4 2 Link to comment Share on other sites More sharing options...
ak2m4 Posted August 6 Share Posted August 6 3 minutes ago, Lozart said: Wow, that is OLD! Jurassic Army. Look at the size of the vent holes in the piston head. Length of the cylinder head shaft looks quite long as well. Looks all nice and clean, cheap to fix up and run Lozart and Colin Allen 2 Link to comment Share on other sites More sharing options...
Supporters Lozart Posted August 6 Supporters Share Posted August 6 3 minutes ago, ak2m4 said: Jurassic Army. Look at the size of the vent holes in the piston head. Length of the cylinder head shaft looks quite long as well. Looks all nice and clean, cheap to fix up and run I was just thinking that, it's in bloody good nick for its age! Link to comment Share on other sites More sharing options...
Colin Allen Posted August 6 Share Posted August 6 1 hour ago, Lozart said: Wow, that is OLD! The different design of tappet plate would certainly account for what you're seeing. The fix will still be a longer nozzle though as you can't get tappet plates like that any more. He could try fitting a standard tappet plate and seeing how that goes; it might still need a different nozzle. Lozart 1 Link to comment Share on other sites More sharing options...
Supporters Lozart Posted August 6 Supporters Share Posted August 6 1 minute ago, Colin Allen said: He could try fitting a standard tappet plate and seeing how that goes; it might still need a different nozzle. Absolutely, other than being drier than a nuns fanny it seems to be in pretty good nick. Link to comment Share on other sites More sharing options...
Colin Allen Posted August 6 Share Posted August 6 2 hours ago, Lozart said: Absolutely, other than being drier than a nuns fanny it seems to be in pretty good nick. It is surprising how good some gearboxes look after a long period. I opened up the lad’s blowback G&G AKM on Sunday to deal with a low power issue, after it had not been opened for many years. Apart from a worn piston head O ring, it was pretty much perfect. it was still a bugger to do due to the stupid pneumatic blowback system. ak2m4 and Lozart 2 Link to comment Share on other sites More sharing options...
Pollynator_bravo2 Posted August 7 Author Share Posted August 7 On 06/08/2024 at 10:38, Lozart said: Absolutely, other than being drier than a nuns fanny it seems to be in pretty good nick. That was before being cleaned and lubed up. Was wetter than Gemma Collins mouth in greggs On 06/08/2024 at 12:59, Colin Allen said: It is surprising how good some gearboxes look after a long period. I opened up the lad’s blowback G&G AKM on Sunday to deal with a low power issue, after it had not been opened for many years. Apart from a worn piston head O ring, it was pretty much perfect. it was still a bugger to do due to the stupid pneumatic blowback system. What’s the correct O ring size for the piston and cylinder head ? Rogerborg and Lozart 2 Link to comment Share on other sites More sharing options...
Colin Allen Posted August 7 Share Posted August 7 (edited) 1 hour ago, Pollynator_bravo2 said: What’s the correct O ring size for the piston and cylinder head ? Cylinder head is generally 22mm OD, 1.5mm cross section. Piston head is generally 24mm OD, 2.4mm cross section AK2M4 sells some slightly larger piston head O rings for slightly larger cylinders; they are 24mm OD, 2.7mm cross section. Edited August 7 by Colin Allen Pollynator_bravo2, ak2m4, Dan Robinson and 1 other 2 2 Link to comment Share on other sites More sharing options...
Pollynator_bravo2 Posted August 11 Author Share Posted August 11 On 07/08/2024 at 21:16, Colin Allen said: Cylinder head is generally 22mm OD, 1.5mm cross section. Piston head is generally 24mm OD, 2.4mm cross section AK2M4 sells some slightly larger piston head O rings for slightly larger cylinders; they are 24mm OD, 2.7mm cross section. Epic thanks for this. Next job on the list 😄 Link to comment Share on other sites More sharing options...
Big Cheese Posted September 18 Share Posted September 18 Compression test the cylinder. With the cylinder out of GB with tappet and nozzle fitted. Hold finger over nozzle and push piston down into cylinder. It should stop 2/3 way down when all air is compressed. If it doesn't replace the piston oring. Link to comment Share on other sites More sharing options...
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