Did I make a big mistake? I bought a Yong Heng compressor from China!!

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@kayakairgun- Sorry to hear about the 2nd stage piston failure. Great idea to start up a new thread to follow the repair process. I was thinking about compiling the information learned so far from messing around with the YH here and starting a new thread for it entitled something like "YH Compressors - performance, specifications and repair", just as a catch-all for things like fitting sizes, nominal pressures and temperatures, part numbers and ratings, simple repairs and general hints or suggestions. But it's going to take me a few days to collate what info I can find. Do you think that would be a useful thread to start? And if so, please keep it in mind as you go through your piston replacement because I think the things you learn while doing that would be good information for it.
 
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I think that would be a great idea. Having information centralized and in a format that easy to read, understand would be a great asset to the air gun community. I think the yong heng compressors are a great thing, I love having cheap air, it just may come at a price of having to work on them to keep them running. Witch I don't mind at all, the lil compressor has allowed me to shoot more in the last 2 months than I did in 3 years owning PCP'S and a hand pump.
 
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I have started gathering basic info about the YH compressors - thought you (@kayakairgun) might find the fittings sizes helpful, so while I will request a new thread once the info is more organized, here are some pics with fittings sizes labeled for you. I matched the fittings by actually checking them against a thread and pitch gauge like this one: https://www.amazon.com/dp/B003FJW0GK/ref=cm_sw_r_tw_dp_U_x_3uNxAb63T009N

So in the meantime, here you go.
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I have been reading this and all posts relating to this Yong Heng compressor and it seems like a great value. It also seems most problems with it have been minor like loose connections and other easy owner fixable things. In light of all these posts and videos I have seen I went ahead and order the 110 volt version with the set pressure gauge. As far as the lubricant I am tending towards using the Royal Purple Synfilm 100 compressor oil. Does anybody know how much it takes to fill this compressor. It would seems the better value would be to buy the one gallon size. I also ordered the gold water/oil separator, some activated alumina 1/8" beads and desiccant indicator beads. I intend to do the pcv pipe insert to hopefully to improve performance. I do have a Joe Brancato Great White Tank and fill line. My question am I basically needing to to replace the male foster on the gold filter with a metric M10x1.0 to 1/8 bssp male/male then a 1/8" bssp male foster w/ female threads. In other words these two linked items. Bill
Item 9004-02-10
www.discounthydraulichose.com/9004_BSPP_x_Metric_p/9004.htm

www.pyramydair.com/s/a/Air_Venturi_Male_Quick_Disconnect_1_8_BSPP_Female_Threads_Steel_Rated_to_5000_PSI_Incl_Delrin_Seal/3550
 
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"prfssrlee"@AirgunBill - I think you just need a male-to-male foster fitting, assuming the fitting on the end of your fill line is the same female foster fitting that is on the end of the YH line. That is, one of these for $10:
https://www.amazon.com/dp/B073TKN54S/ref=cm_sw_r_tw_dp_U_x_tBoCAbA3B8GFV
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Okay I watched one of the videos using the gold filter and provided first stage black filter. I think using the small provided first stage filter is good to use to pick up oil and other contaminants. So the compressor's black filter female foster connects to the gold filters male foster. The other hose end connected to the gold filter terminates with the female foster QD. The fitting you showed would connect my Joe B hose to the gold filter female foster hose. So, just to clarify the fitting you listed is supposed to take care of the compatibility issue between the two female foster fittings? Thanks Bill
 
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"AirgunBill"I have been reading this and all posts relating to this Yong Heng compressor and it seems like a great value. It also seems most problems with it have been minor like loose connections and other easy owner fixable things. In light of all these posts and videos I have seen I went ahead and order the 110 volt version with the set pressure gauge. As far as the lubricant I am tending towards using the Royal Purple Synfilm 100 compressor oil. Does anybody know how much it takes to fill this compressor. It would seems the better value would be to buy the one gallon size. I also ordered the gold water/oil separator, some activated alumina 1/8" beads and desiccant indicator beads. I intend to do the pcv pipe insert to hopefully to improve performance. I do have a Joe Brancato Great White Tank and fill line. My question am I basically needing to to replace the male foster on the gold filter with a metric M10x1.0 to 1/8 bssp male/male then a 1/8" bssp male foster w/ female threads. In other words these two linked items. Bill
Item 9004-02-10
www.discounthydraulichose.com/9004_BSPP_x_Metric_p/9004.htm
www.pyramydair.com/s/a/Air_Venturi_Male_Quick_Disconnect_1_8_BSPP_Female_Threads_Steel_Rated_to_5000_PSI_Incl_Delrin_Seal/3550
Click to expand...
Hi Bill
Why don't you just use male Foster with 10x1mm thread. You will get the same result and eliminate two junctions. I just cut a new thread over the one that I want to change but I do not recommend doing this as it may or may not weaken the joint. The name Foster fitting is just a generic term for a 1/8 QD coupling. There are many companies making these things and some are compatible with each other and some are not. The origional Foster brand ones are probably the best but probably the most expensive. These Chinese compressors are confusing things more by using metric threads. I hope this does not confuse you any more.
Regards Ian.
 
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I think I can figure it out it just depends on how I want to solve the potential problem of the gold filter exit hose foster not connecting to my Great Whites male foster. Look at this video done by I believe a member here that shows the hook-up using the gold filter. Advance to the 25min and 40sec. point. Supposedly the gold filter female foster might not connect to my USA made male foster. I just rather not use the gold filters exit hose and replace it with the metric to 1/8'" bssp male connector and add the male Venturi fitting I mention. That way I can use in my opinion better made hose. Anyway I try things as is and see if the connector work. By the way does anyone have an answer to how much hydraulic oil this compressor holds. Bill
Video

My tank
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Air Venturi Fitting
https://www.pyramydair.com/s/a/Air_Venturi_Male_Quick_Disconnect_1_8_BSPP_Female_Threads_Steel_Rated_to_5000_PSI_Incl_Delrin_Seal/3550
 
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You've got the gist of it. By the way, if you want to connect the small filter to the gold one as in that video, the fittings are compatible with each other. Probably made at the same place. I don't have the Yong Heng pump but I'm guessing it would only hold about 250-300 ML. I would not be too concerned about using top shelf oil. I think anything that is slippery will lubricate the bottom end well enough to outlast the electric motor IMHO.
 
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The threaded hole on the gold filter is M10-1.0 (on both ends), the threaded hole in the smaller black air filter is also M10-1.0. At least, that's the case for both of mine (as well as for some even smaller anodized aluminum filters that came with my hand pump. 1/8"BSPP is 28tpi, not M10-1.0, which has a pitch of 1.0mm. It's a bit nuts, but I've found English standard (ie, npt), metric standard and BSPP fittings on my Yong Heng compressor. 
 
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"prfssrlee"The threaded hole on the gold filter is M10-1.0 (on both ends), the threaded hole in the smaller black air filter is also M10-1.0. At least, that's the case for both of mine (as well as for some even smaller anodized aluminum filters that came with my hand pump. 1/8"BSPP is 28tpi, not M10-1.0, which has a pitch of 1.0mm. It's a bit nuts, but I've found English standard (ie, npt), metric standard and BSPP fittings on my Yong Heng compressor.
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prfssrlee I actually got my Tuxing filter today and it is not compatible with the Joe B. foster fittings. I will keep the inlet male foster on the Tuxing to hook-up the first stage filter but have ordered the proper male metric to 1/8' bspp fitting and an Air Venturi male foster with female threads so I can use my Joe B. fill hose instead of theirs. I hope this works. By the way I ordered my Yong Heng a few days ago and got a message that it is preparing to ship. I hope this is a faster process. Bill
 
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Interesting. I know each end tapped on the gold filter is M10*1, but 1/8” NPT fits just fine. I used a 1/8” npt male foster before I knew the correct size. It’s been on there for many months. The other end has the M10*1 male foster, and that screws in further that the 1/8” npt, but both screw in far enough to be safe and leak free. 
 
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@Centercut- Yes, 1/8"npt is 27tpi, which is almost 1.0metric (which would technically be 25.4tpi) so it does screw in a good ways and can seal. The bigger difference is that the sealing on npt threads is done with the threads (which is why they are tapered and why you probably used teflon tape), but the M10-1.0 thread is mainly intended to be face-sealed with that little white teflon gasket inside (which is why the threads are parallel). At least, that's how I understand it.

I bet your 1/8"npt is stainless steel and the hole is aluminum, so you are engaging enough of the threads and deforming the aluminum so don't have an issue. My guess is you wouldn't want to do the reverse - ie, thread an aluminum npt male into a stainless metric female - because then you'd be deforming the male threads and have the possibility of thread failure.
 
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Yes, I do think you’re correct. The male foster that came with the filter screws in almost all the way but I think it’s still a thread seal and I used Teflon tape on that one also. It is maybe one thread from making contact with the end cap. The other side with the npt thread is about 3 threads from being all the way in but still has about 4 threads engagement and I also used Teflon tape. 
 
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I really appreciate this thread and all the time it took to compile all this information and take the pictures. I have not had any problems with the Yong Heng compressor, but I saw the title of this thread and spit my coke out my nostrils because I thought the exact same thing when I bought mine. Hopefully this thread never comes in handy, but I have a feeling that I will be back. :) 
 
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I agree with Centercut and prfssrlee. All three 1/8 bspp 1/8 npt and 10x1 mm are very similar and some will fit one way but not the other. The 1/8npt male will screw into 1/8 bspp female until it binds on the taper but 1/8 bspp will not screw into 1/8 npt female at all and then you have bspt which I don't think is compatible with anything. That is why I just cut the thread that I need over whatever I have but only once and I only cut parallel over taper, never the other way round. I wish that everybody could agree on one standard but that is never gunna happen. prfssrlee is right about using Teflon tape on the tapers and washers, O-rings or molded washers on the parallel ones with a mixture of both when marrying two different types. As for the different QD fittings, even if they seem compatible, they sometimes damage the O-rings and let go towards the end of the fill. That is why I use a non-return fitting on the bottle side so I don't lose the whole fill if one goes when I'm not nearby. That really makes my brown eye blue. Hey Bill, try this. I ordered a couple myself.​https://www.ebay.com.au/itm/292235740409
 
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