Canadian Airgun Forum

One of my Yong Heng clone compressors has been limited to ~4,000 PSI and very slow to raise pressure much above 3,000 PSI.

I hadn't bothered much about that because I use that one for pumping guns at home, so it only began to be a factor for FX Streamline and PP750, which fill to 3,500 PSI, although it still did the job.

My concern was that my #3 compressor was the only one which did a strong job of filling my 4,500 PSI SCBA tank and I wanted a spare.

It just occurred to me that replacement high-pressure piston cups might be thinner at the bottom, and so reducing compression ratio.

I did some measuring, added a washer between the piston cup and the push/piston rod, then made spacer washers to place inside the piston cup, under the Allen screw.

The modification got both #1 and #2 up to full pressure.

I'm laughing at myself since that eventuality just came to mind, but maybe it will help someone else.

I've not been successful in posting photos to this group but the write up is in a MeWe group: https://mewe.com/join/yonghengcompressorsandclones

I will leave these photos in Dropbox for a while: https://www.dropbox.com/scl/fo/6g9wjbx2 ... irqkee9lwi

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Slavia 618 .177
Webley Senior .22
Jelly SUPER 4.5 mm
Webley Viscount .177
Kral Mega Marine Walnut .22
Artemis PP750 .22
FX Streamline .22 walnut
FX Streamline .22 composite
FX Dynamic 500 .22

I couldn't access MeWe to read the write up, but I was able to download the photos from dropbox and I'll add them below for reference:

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Iacio, ergo sum

last one, 3 is the limit per post.

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))))----//----------==
Iacio, ergo sum