I've rebuilt alot of engine's including high performance, all parts should be lubricated when being assembled, including the 'O' rings, all of them. 'O' rings can be damaged when assembled dry. Proper lubrication of the entire piston assembly is crucial, as a dry start up can cause significant damage, especially to the crank pin. This is why these things spit alot of oil when new, the excess oil being used when assembled in the factory. You don't need to drown it in oil, simply use a light coat of oil on all moving surfaces. This is probably why it wouldn't start up initially, the cylinder walls were dry. I'm surprised this thing survived the initial start up, the piston rings especially. Otherwise, it was a very good tutorial.

Great video. When you turn on make sure all valves are open. Once the compressor is running then close the valves. Doing this on startup does two things it keeps the motor start up Amps low and 2nd less stress on the piston at startup.

I think that changing the entire piston is key when the old one is having trouble getting past 4000 psi. The first stage rings are worn out as well as the second stage. I only replaced the high pressure rings on top and still had the same issue. Definitely replace the entire piston assembly and maybe wipe the inside of the cylinder with a little bit of the Diester oil for start up lubrication also. Very helpful video bud. Thank you.

Another fine video production from the AVS desk! Great information and very useful tips bud. Thank you for taking the time to setup, video capture and the multiple hours of editing necessary for us to sit in a lazy boy and enjoy!

Excellent video for understanding the order of operations regardless of machine. I don’t have the exact same machine - but mine is still going strong after 4 years at the moment. This definitely would’ve helped me tremendously the first time I cleaned it

Very timely YH information Stephen, thank you.

Great video. Thank you much. Mine is about two and a half years old. I run it about once a month for a 6.5 L bottle. I've never let the bottle pressure goes down bellow 200 bar. I've notice that oil is getting dark....probably l need to do the same job. By the way...my first PCP was a Nova Vista Alpha...I still have and love it. Thanks for the great reviews on that gun.

Great information. Mine has been running flawless for two years now. I went ahead and ordered the spares I may need in the future. I had two other compressors that cost much more and went bad very quickly.

I HIGHLY RECOMMEND this short and thorough break down video of the Yong Heng. SPECIAL NOTE OF APPRECIATION: to the bullet point editing along with still close-up photos and explanations of integral parts. Stephen, this will serve many who own Yong Hengs. A deft piece of work!

You make the best informational videos on Airguns and related subjects on KZfaq. Thank you for sharing this information!

Just wanted to say thank you for all the videos that have kept me safe and saved me time and money thx

I appreciate you taking the time to shoot these videos. Very much appreciated....

I just did the same thing to mine . I had mine 21/2 years. It just started making a noise and like you said was not pumping as fast as it was but it was still working. I could hook my gun to it and it would fill it just not my tank . It’s so easy to do . People say what a piece of crap this is but I love it . For what it cost it’s well worth the money. And the parts are easy to get and not hard to rebuild. Great video. Thank you so much

Great tear down video. I can't thank you enough for sharing this.

Always great info Stephen.

Just subscribed from the UK.. Great Vid. I've used my Yong Heng 4 times now... Love it and thank you for all your great tips and tricks.. As a guestimate how many times have you used this in the 3 years before its needed this major overall.. Cheers from Blighty 🍺😂

Great job! I hope you get another 3-4 years out of it, i have had mine going 3 years now, i only used the aw-46 for a short while, i am hoping it will continue to last seeing how i only pump up guns with it, i did buy a backup compressor and have used it for a month now and plan on mothballing it and use my 1st one till it has an issue, thanks for all you do, very informative, thanks!

Excellent video. I really enjoyed it, and welcome back, sir.

Excellent and very informative as always.

As always, another great video!

Muy buen video !! Excelente! Saludos desde Argentina 🇦🇷 genio!

your videos are amaizing thankyou for being so great 👍🏻👍🏻👍🏻 always love watching them

very good brother thanks for the video, I have one of this and it is very good I have 3 years with it and I only buy maintenance parts just like you

Wow that was excellent extremely helpful thank you very much props to a very well done help guide video 👍👍

Another awesome and informative video!!!

Mine was just delivered today. Hopefully it's 2 or 3 years before I have to do anything like this. Thanks for sharing all of your knowledge and eperience with your YH's you've owned. You're videos are a large part of the reason I decided to go with YH. Thanks. Much appreciated.

I use the all season select synthetic lubricant some guy that using the youg heng compresser suggested for me to use it so I've been using it but I only use it for filling my air guns no tanks yet thanks for sharing your experience with this compressor

What helps is to have a dehumidifier set to the lowest humidity possible in the room your compressor is running in . Thanks for sharing your experience with these compressors and dryers .

Great info as always! Thanks for sharing.

Fantastic video ,very informative.

I ordered the piston after watching this video. The eBay seller sent me one that was larger than mine. After repeated tries I measured it . The time I spent and the cost for the piston wasn’t worth it. I still have a 220 volt Yong heng which I will use until it breaks but I do like my new CS3 GX which can be used on battery power.

Next time you have the blue cover off, make note of the capacitor value and get yourself one as a spare. Next time it just buzzes and has no mechanical obstruction, you'll be grateful you followed this advice

Awesome video thanks for the info!!

maybe your best video

Hi. I really love your videos. The amount of information you share is awesome. Can you also make a teardown video on mini gx cs2 air compressor some day

Very helpful, thank you.

Best channel

My check valve shredded too. I replaced it with a billet on made from stainless. Worked great! I also opened up the piston arm and pressed a bearing in there an turned the crank down to fit the new bearing. Worked fabulous and ran alot less hot too

I have mine only used it 12 hrs 30min timecto fill my bottal Oil changed ever 3 hrs How hours use over 3 years have you done.

ótimo vídeo meu amigo muito bem explicado

That stalling issue is most likely because you start it with both bleed valves closed. When I top up my tank I start by opening the valve on the tank to pressurize everything and check for leaks, high pressure bleed valve closed of course, then with the low pressure bleed valve open I start it and then close the low pressure bleed valve and fill the tank. Perhaps I should make a quick YT video of the starting and stopping procedures I have found to work that I use? If or perhaps rather when, the top of my second stage piston breaks I'll make a new one of stainless steel, just the top part not the whole piston. :-) Very informative as usual! Big thumbs up!

Great video Stephen. What are the chances you could attach a link for the piston and swingarm from Ali Express? It's been my experience that the piston is the point of failure on this style of compressor 90% of the time. As you know (since we communicate in the "real world") my compressor just recently crapped out on me. I thought that perhaps it was caused by the change from Royal Purple to Seco Lube, but more than likely it was just ironic that it happened to fail after I switched. I believe it's only a matter of time before everyone experiences a failure with their piston in one form or another. I've experienced a cracked head, and now the attachment point on the swing arm to the crank shaft has canted, and since the swing arm is aluminum, and the crank shaft is iron, the aluminum gets warm, malleable, and gums up on the inside and eventually seizes. The piston on these pumps is definitely the Achilles heel. These issues could be resolved by using a thicker casting, or ideally a milled piston head, and a steel bearing inserted into the swing arm where it seat on the crank shaft. But unfortunately these items are manufactured in China, and the QC of the products is HIGHLY lacking. Also, regarding your 90 duro o-rings, I recommend swapping them out with 90 Durometer Cast Disogrin Urethane O-Rings. They are designed for EXTREME pressure situations, and they are FAR more durable than the 90 durometer o-rings you're using now. They can be purchased from the o-ring store ( www.theoringstore.com/store/index.php?main_page=index&cPath=367_1322 ) online. Unfortunately the site has limited selection of these o-rings in metric, but you can run the numbers through a conversion calculator and get the closest size to the metric equivalent. I've NEVER had one of these o-rings fail on me. They're rated at 6000+ psi, and they temperature variance range on them is -115° to +250F°. You'll need to know the exact size of the other o-rings or use a caliper to do the conversion. It's better to have the ID slightly smaller than the original metric ones, and the OD slightly larger when replacing.

thanks for the video....just purchased my yong heng compressor. first couple of times i filled the gun, too a matter of 30 sec. Now on maybe my 7th fill, it takes over a min to get to 1000psi....any ideas of what I should look for. I did use the block end on the fill tube and take a very long time. I dont hear any leaks. this is a new compressor, the O-rings should not be worn yet. ( have kept it cool). Before I rip the thing apart, I thought I would check with you first. Thanks CO

Fantastic video! I had my Yong Heng compressor for about 3 years. I know it needs some maintenance. Mine is recently Sounding like it's bogging down when I fill up my air rifle, it doesn't happen all the time but it is happening more frequently. If somebody could give me a heads up on where to look when I tear mines down that'll be very appreciative thank you.

Hi, Thank you for your Yong Heng series, I really find it useful and I am "one step behind you", following your recommendations that is, I see many reviews talking about the water damage inside the cooling system, what would you say of using automotive cooling fluid, same as we use in cars radiators? else, would you use distilled water? Thank you

When installing the piston into the jug it's a good idea to clock the rings so the gaps are at different locations around the diameter to help prevent blow-by.

Sugestion I noticed you did not pre lube the o-rings on high pressure piston or rod bearing I feel like that may have helped on your start up maybe a little silacone grease .

hello where did you find the compressor part the high pressure piston i have a vevor it looks like the one you have it take 20 plus mins to go from 3000 to 4000 psi and im wondering if you know where i can get the new seals for the high side

My Yong Heng auto shut-off compressor purchased two years ago has been operating strangely. When filling a 3L carbon fiber bottle it runs for one or two minutes then stops. After one or two more minutes it starts up again - by itself and without opening either the drain valve or the pressure relief valve. The temperature is low (40-50 C) and there are no apparent air leaks. I did notice some air coming out of the "breather/oil inject" relief hole but no leaks anywhere else. I am using a 5 gallon water cooling bucket and a fan behind the unit for cooling. As I understand it this compressor does not have a thermocouple cutoff. Have you experienced this? Any thoughts? Thanks!

How do you change the high pressure seals on the brass shaft? Does the rod unscrew from the large piston or from the top of the brass stem?

Hi Steve from Suffolk UK 🇬🇧 I found after running the compressor for an hour or two at 15 minute intervals I needed to change the oil because of a lot of very fine grey particles in the new oil?😊👍

Hi Do you use the water facility to cool the cylinder or not bother when running ?

Please post a link to where you purchased the replacement piston assembly. Thank you and have a most awesome evening!

I do Cerakote finishes. I wonder if that would help with the corrosion? They make some coatings that are used on engines. I'm a fellow LI guy. Let me know I can coat yours and see if it helps. I need to order a compressor myself.

Would you recommend soaking dirty , or build up parts over night in distilled vinegar?

Can you add links to where you got the spares?

Does the Compressor Diesel/Combust oil while pumping ? That would resolve where the carbon comes from.

Did you really assemble everything dry?...oh boy..you need to take that thing apart and replace all o-rings/and seals and reassemble lubricated..im sure everything was damaged in the first 10 seconds of starting it...other than that small detail great video and i found it very informative...

Hello, thank you for making such great videos. So I have a compressor and once I stop filling I stop the compressor and need to bleed the hose. However, If I slowly bleed the compressor the rifle's valve won't close and will vent all the air in the tank. If I rapidly bleed the air from the compressor the piston valve of the compressor will go bad. Could you please tell me what additional valves I need so I can shut the compressor and then bleed the air safely? Thank you!

I only have about 6mo of light use on mine. Wont get over 1000psi now Thoughts?

What is the name of the oil that you use in your young hang and where can I buy it

I got 3 running hours out of my last Yong Heng. I have had 4 or 5 of them. Not going back. Looking hard at the GX CS4.

Any upgrades for a Kral Super Duty .22?

Where did you get the replacement parts?

Is there any place that sells the "o" ring for the check valve of YongHeng without buying the whole kit ?

You should have honed the cylinder, and lubricated the piston rings on both pistons. Engine assembly lube would work the best. The cast iron piston rings are much softer than the cylinder wall. When a set of carst rings are assemble dry, when the piston is moved, it will allow a small amount of the cast to deform. Once the very small bit of cast is moved on the ring it can then bite into the cylinder wall. Which will make the motor hard to start. Just a possible answer.

Question: is the Ester oil you recommended sold commonly as A/C compressor oil? Been checking local auto supply stores. That's all I can find. Thx

The nomad compressor says to add 2 drops of oil to the air inlet every 5 fills do you add oil to the inlet also with this compressor Thank you

I took apart my youg heng compressor dam it was dirty bad im going to change lubricant to the one you have there hopefully it will be better I mean the one I use seems to work good I never smell anything like burnt or anything but after taking it apart the brass deal in the middle was freaking dirty bad

I'm having a weird leak somewhere from the compressor that's coming from under and behind the block, it seems like it would be the 'rear main seal' near an output or input shaft , but it doesn't leak any oil and will fill to about 3,000 psi and Just won't go any higher. When I shut the compressor off there is a steady leak somewhere. I've checked all over the immediately available area when I take the blue shroud top off, it seems to be coming from somewhere in between the cylinder block and the electric motor. Any ideas?

Hi can you tell us corect size of that two spacer and is it made of derlin plastic , large ring and smoler one , and when you putin on place ist important wich side is caming biger spacer

1:12 kind of amazing, isn't it?. You get a compressor that is cheaper then anything else on the market and they even give you replacement parts. I love mine. It would be perfect if they could reduce the noise by a few dBs

Where did you order your parts? I got screwed on marketplace. Figured id take a chance because im poor. Saved a year to get my umarex. You get four shots because its a big bore. But the pump worked decent once, didn't get to 2 k that fast though... And its water cooled. Im trying to find the air that is leaking into cooling pump. Figure its the main seals because it wouldn't get over 3400 psi today. Help would be more than appreciated 🙏🏻

I am starting to see that my compressor is taking longer to fill my big bottle. Now I see that it won't compress more than 250bar. I would imagine that it is the high pressure piston rings. I will pull mine down and see what's going on. I really baby this compressor. I never run it more than 10 minutes or 60c. Unfortunately, I only have 7 1/2 hours on it and it is failing. Anything else I should be looking at?

Quick question, I filled my tank to 4500psi and I mistakenly closed the valve on the tank before turning off the compressor or releasing the air from the drain screws and now my Yong Heng compressor blows air out of the black oil fill cap instead of the fill hose, do you have any idea of what the issue could be I would really appreciate it ,TIA

Anyone know if there is interchange between the parts on the Yong Heng and same or similar designed Vevor, if they're the same design at all?

Good vid but! The spacers on the gudgeon pin being of two different sizes, suggest to me that there is a thrust side for the piston! Dry fitting of the piston, rings and bore? Never try to start the compressor under load, open the pressure relief valve, start and then close the valve when running. The same applies to stopping the motor..

Just a question do you think that after you rebuild the compressor that it should be run for 5 minutes to break in similar to low psi compressors then pressurize?

Do you recommend any lubricant on the piston when assembling into the cylinder?

My yong Heng want build pressure above about 2000 psi. It is 2 months old. I took it apart and the piston and o rings look good. With it hooked to an scba cylinder with 2000 psi in the cylinder and the pump running I am getting high pressure air coming out of the oil reservoir vent plug. Any ideas? Thanks.

Wow... very good. Sealing ring piston. What's the material? thanks.

Did your friend decide to start selling the stabling stand for the Yong Heng? If so what is the price, and how do I contact him?

Olá. Como trocar os orings do pistão? Esse que quebrou? Ajuda aí por favor 🙏 😅

Its quite hard to replace the second stage seals, the end screws off but you need a custom grip tool to do it, otherwise you will damage the brass, best to just buy a new piston assembly like you have. The second stage head needs regular cleaning of the reed valves.

I just order a Holymus yong heng 4500 psi 30 mpa but the black label on the right side spelled it yongyineng ,How did they spell it on yours, Do you thing wal mart is selling knockoffs ? Thank you Bruce.

compressor gx cs3 or yang heng In terms of device life ؟

Good info, but I didnt see you lube this piston o-rings with the hydraulic fluid... That's necessary!

I have replaced today the burst disk but it dosen`t s work It continue to darán air. What can I do? Thanks

Exact same issue. Same age, happened christmas 21.

I realize this is an old video, however, if you are getting carbon buildup on the parts it is a sign of detonation which isn't good. Detonation is due to the oil being used not having a high enough flash point and probably the incorrect oil for the job. Oils made for high-pressure compressors won't cause carbon buildup as they have a sufficiently high enough flash point to prevent it. Had the same problem as shown above after one year with my Yong Heng, haven't had that problem since changing oils, and the compressor is over 5 years old now.

Hello, it's been a while since the video... One question... I have the same compressor. Is it normal that the red valve always releases air intermittently at slightly higher pressure? Maybe someone knows an answer?

How many hours are on that compressor? And are parts easy to find for this compressor? I’ve been thinking about getting one.

When you break in that compressor, be it new or serviced, you should run it for about 10 minutes with no load, then load it intermittently every 30 seconds or so for about another 5-10 minutes

Has anyone had air leak in to the water for the pump?

Anyone tried running two of these in parallel to fill a single tank?

By installing the piston the way you did it, Just destroyed the 3 high pressure rings, Cause you didn't separate the top half, Is ring pieces are now on top of your piston.

A thought for clean up wouldn't a ultrasonic cleaning tank work the best and also clean the crap out of the water separator the best.

you should always apply some lube when reassembling the piston and cylinder or else it might get damaged instantly

Maybe a little neverseeze on the stainless fittings. Just enough to stop gulling The lube you use is expensive. Mobil makes a compressor oil that is cheaper . You really don’t need compressor oil rated for breathing air. Just saying. Awesome video…

Yong Heng, there's no need to break down I said, Yong Heng, pick yourself off the ground I said, Yong Heng, 'cause you're in a new town There's no need to be unhappy