Asahi M134 Minigun Teardown
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As I said on the previous page the Asahi minigun came with a instructional video on VHS tape. Even though it is in Japanese you will get a basic understanding of the gun & some maintenance footage of what is involved to care for your gun. The word I must emphasize here is basic! There is nothing basic or simple about this gun, the center chunk or rotor of this mini is more complex than the real-steel original! This gun needs a instructional tape at a minimum of 30 mins and really should be an hour to cover what you need to know to keep your Asahi in good operational condition. So here we present a photo teardown of the Asahi with brief explanation of the parts & how they all come together to form one of the most complex airguns to ever come out of Japan.
Receiver BodyThe Asahi frame comes apart in 2 main sections, the front face & rear body.
With the inspection cover removed you can see the gas inlet on the rear rotor central axis, a high speed rotational gas fitting allows a semi-flexible tube to connect to the spinning rotor that houses all 6 gas valves & BB chambers. The remainder of the rear receiver is normally empty except for the gas tube (Not shown) and the battery pack that slides out the rear of the gun. Another difference on the Asahi, no removable safing sector on the gun body. Instead the pins hold the false cam path groove in place, if you remove them the circular cam path area slides back to expose the 4 screws that hold the two receiver halves together.
Barrel Retainers & Bearings
The movement of the inner barrels is accomplished with this cam ring & bearing system. It allows the individual barrels to move back and forth pushing the bolt into position, allowing the BB to enter the chamber. Then as the barrel cluster rotates to the fire position the chamber is sealed as the bolt and barrels move forward. Upon sealing, the rear cam depresses the pin of the gas valve on the rotor assembly to the rear, the gas then flows through the hollow bolt, comes in contact with the rear side of the pellet & the pressure difference causes the BB to be expelled out the barrel of the gun.
Barrel Guides & Bearing Close Up
Don't be skimpy on grease when it comes to the cam ring, notice the grooves worn into it. It appears one of the bearings had given way in the past but the gun continued to be used.
Bolt head & spring
More small parts, the Asahi bolt is hollow & has a hole in the front section to allow the BB to be forced into the chamber. As the barrels rotate to the firing position the bolt moves forward this hole is sealed off. If a cheap BB does not make it all the way in, it's fate is the same as chicken at a Japanese grill restaurant, Chop Chop Chop!
Front Rotor Face & Chambers
The white plastic ring is the stationary BB pickup guide.
BB pickup/false motor head. BB's are forced down into this by the spring loaded piston housed in the fake motor body. Notice the dual set of "Teeth" on the feed rotor, as the BB's near the exit tube at the top a stationary ramp between these teeth force the BB's up & out through the brass nozzle pictured below. To prevent the BB's from becoming stacked up and trapped in the dead area of the pickup a "Stirring rod" is attached to the main drive shaft and rotates with the feed mechanism.
Complete motor head assembly with feed port, gear drive for the pickup rotor & stirring rod. This system also uses an adjustable clutch drive to prevent total destruction of the system incase of jamming. If the BB's get stuck & after a certain torque limit is reached the stirring rod and pickup teeth will cease to spin but the main rotor will not in an attempt to clear the jam thus limiting destruction to just the BB's themselves.
Forward Receiver & Guide
About 6000 rounds a min are supposed to feed through this little hole. As the chambers came into the correct position a light burst of gas was discharged by the trigger ring this light burst created a small vacuum in the chamber and would suck the BB into chamber port. If the BB does not make it all the way in the little metal strip "helps" it & here is where the major problems start. A bit off center or only half way in as the gap closes and if not in perfect alignment, the BB is crushed flat & you are pulling shredded airsoft pellets out for the next hour. If you are not any wiser to the changing sound of the gun & keep the trigger down you end up with a new inner plastic ring, made out of a freshly shredded and or melted mass of what a few seconds before was your ammo! This is why the manufacturers went to great length to make the all important point - Normal airsoft pellets should NEVER be used in a Asahi 134!
Rotor & Rear Bearing
Complete rotor with trigger arms & a unusual dual face main bearing
Chamber & Valve Body
Disassembled chamber & valve with manifold connector. In this picture you can see the underside of the chamber that faces the central axis of the rotor. The left end of the valve pin is the tip that protrudes through the top pf the chamber to be depressed by the trigger arm as it spins into correct position to fire
This is a picture of the rotor with the gas trigger arms removed leaving the valve pins exposed. The main bearing is has also been removed exposing the manifold that is also used as a bearing surface. The gas connector at the rear spins to allow rotation with the flexible gas supply attached. Gas only flows into the unit when the trigger in the handle is depressed to prevent leakage when the gun is at rest. The handle itself contains a unique high flow valve as well as the electrical motor power supply switch.
Chambers & Gas Manifold
Stripped manifold with 1 chamber removed
Stripped Central Rotor Core
I would hate to have to replace this, doubt Asahi kept any of these and unless you have access to a good machine shop and alot of skill it will cost big bucks to have one of these made!
Shims No More..
This is a picture of the shims that protect the rotor. In this gun the shims had totally disintegrated, some had fallen out of the gun but it was used after the fact. Important Note: Airsoft owners, If you see pieces of anything other than spent cases falling out of any gun, Stop Shooting! Nothing good can be happening inside it!
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