Problematic piston valve

[jma78]

This is a question for the highly skilled repair guys!

I have a Meinl Weston Thor that I bought new a couple of years ago. Aparently the first valve piston diameter was a bit too small from the factory. Because of this, the piston easily got stuck in the bottom position, if not pressed down very straight.

So, a couple of months ago I had the piston replaced at the factory in Geretsried. When mentioning that the new piston didn't move as freely/easily as the other ones, I was told it needed some time to "break it in"....

A couple of weeks ago I had a good repair guy have a look at the valve. He could also feel that the first valve was not as smooth as the others. But he didn't want to use "grinding paste" to make it move easier. He said the even if he would use his finest/thinnest grinding paste he could easily remove too much.

I'm cleaning the valve thoroughly almost daily and have also tried different oils, hetman and al cass. But the problem still remains.

The piston moves freely the first minute I play. And also if I "slam" the piston down and let i up very quickly it's almost ok. But if I move the valve just a little bit slower, it feels uneven and kind of "greasy" both pressing the piston down and letting it back up.

I would highly appreciate recommendations how to have my repair guy fix this....


Thanks!

[TheHatTuba]

I have the same issue on my school's yamaha sousa. I use a REALLY thin valve oil or, the suggested on this board, water with a couple drops of soap and it seams to help some.

[Ace]

Some years ago, my MW 2145 CC had a sticky first valve. Repeated cleaning and oiling did not help. A tiny burr was found on the valve-guide track, and its removal solved the problem.

Ace

[MajorChubbs]

Are valve guides plastic or metal? I've had more trouble with the metal valve guides tracking in the past (the older king/conn horns).