Terrifying Jinbao tolerances

[Sam Farris]

I was recently making up some new linkages for a buddy's Wessex 410 (his is about 3 years old). While messing around and trying to get the valves to quiet down, I noticed that the back bearing plates were EXTREMELY loose on about 3 of the valves. When I say extremely loose, I mean loose enough that I can completely removed and reassemble the valves with no tools. Just nudging the valve stem with my finger is enough to force the bearing out of the casing. Has anyone dealt with this before? Any solutions or possible fixes?

[Heliconer]

There is a method I have used for swaging back bearings using a lathe and a roller, but if you rush or slip you will lose the bearing completely. Pm me and Ill try to make a drawing/video for ya

[Dan Schultz]

It's no secret that the tolerances on some of the cheaper horns are very poor. Concentricity and fit of the rear bearing plates are critical to the proper operation of rotors.

Peening rear bearing plates or using a @@@@@ punch to hold them in are both risky options. Unless they are VERY loose... I normally don't bother with them once I comfirm rotor alignment. Of course... you can't often depend on the alignment marks, either.

Sure... rear bearing plates that are too tight can be spun down in a lathe once they are properly fixtured. But... again... concentricity is critical.

Sometimes making things right is like trying to make four chair legs all the same length.