Sluggish Rotary Valves

[lucas.barnstead]

Hello all,
As you have read from the title, I am currently struggling with some sluggish rotary's and I am looking for an efficient way to eliminate this problem. I tried pouring warm water down the mouthpiece to rinse them out, sadly didn't work. I soaked them in vinegar overnight then washed off later that morning, still didn't work. I even boiled the valves themselves, yet still no luck. The tuba is a Yamaha YBB-641 and is around 25 years old. I'm no expert. but I would say it has to do with the springs? They are very heavy.
Cheers,
Lucas

[JCradler]

I had a rotor that was sluggish last week. After disassembly, I found mineral deposits on the back plate bearing. I bit of elbow grease and a rag got most of it off. Did you soak the back plates in vinegar? Making sure there is a smooth rotating surface for the bearings helped my situation a great deal. Also check the upper bearing as these are the main contact points. The body of the rotor itself should not be making any firm contact with the outer casing. If this doesn't work, perhaps the valve springs need replaced or adjusted to give more tension. Some folks shy away from this, as it does require more effort to actuate the valve and can lead to fatigue or discomfort(or worse , injury if they are really stiff). Nut, they will move faster. You can also experiment with different oils on those bearings to see if that helps.