YongHeng service pics

[SniperX]

Just sharing some pics from my recent service on the old yongheng.
It was taking a bit longer than usual to fill my tanks.
Usual top off from 3k to 4200 was about 20 min. Recently it's been taking about 30.

There was a bag of orings and seals in the box when I got it. Sure enough, it had the 3 HP seals that I suspected were worn out. The only thing it didn't have was the head gasket, but a trip to autozone for some gasket paper fixed that.

All fixed! 20 min fills are back and the service took about 45 min.

Here are some pics.

Update: The picture below is a bit decieving. There is only one reed valve on the top end. The part in my left hand has a carbon imprint of the reed valve.

 

[Glem.Chally]

Great work! The photos are excellent also.

 

[IMADMAN]

Can the HP seals be found at an automotive shop or small engine repair shop locally?

 

[DesertSilver]

No

 

[Harold999]

Was expecting that my 3 year old Tuxing would be identical inside but the top end (first pic) is different.

 

[bigHUN]

I could not figure out how to replace the 3 HP seal rings and I just replaced the entire brass piston as well.

 

[SniperX]

I could not figure out how to replace the 3 HP seal rings and I just replaced the entire brass piston as well.

I should have taken a video for that part. It is a bit tricky.
To get the old seals off I used an exact knife to carefully cut the hard plastic outer ring. Once those were removed, I used a pick to remove the small green orings that are used to "locate" the plastic seals on the piston.

The pic below shows the seal configuration

To get the new seals on, I removed the green orings from the seals and rolled them on first.
The tricky part is to get the hard plastic seals over the piston.
I first used my knipex "wrench pliers" (the jaws remain parallel when closing) to grab onto the top of the piston and unscrew the top portion. The portion, with the top 2 orings comes off. This allows drop in replacement of the middle plastic seal. For the top and bottom seals, I used the shank of a 1/2" drill bit to roll them into place.

It was a bit tricky the first time but it'll be a piece of cake if I have to do it again.

 

[FIDI_G]

Is there supposed to be any slop between the connecting rod and piston if you pull up and down. I have it out and there is a bit of slop. Also do the small plastic gaskets on the wrist pin do they both go on one side.