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Hello ! Does anyone know where I can buy valve bumpers for a rotary valve tuba ? I`ve got a 4 valve jinbao 200 tuba .Thanks for your time

There are several places where you can purchase rubber cord to make bumpers from. Some folks cut pieces from vacuum cleaner belts. Others use sections from O-rings that can be found at hardware stores. I buy Silicone cord from McMaster-Carr in Chicago.

Size?? I can guide you exactly on that. You'll need to buy a diameter that lets you 'stuff' it into the space provided in the bumper plates so it 'bulges' out. Unscrew the caps on the back of the rotor housings. Then... you'll need to align the rotors using the marks in the center of the rear bearing axle and bearing plate. Before you can use those marks... make sure the mark on the outer edge of the bearing plate is aligned with the mark in the outside edge of the rotor housing. Then... trim the 'bulging' rubber until the marks align in both the forward and back positions.

Rotor alignment is very important to enable a tuba to produce a sound that is well centered. I never rely completely on the marks... especially on Chinese tubas and use a borescope to verify the alignment.

Hello ! Thanks for the reply ! I`ll try the o-rings out i`ve got 1,000`s of them around . My tuba still has the ones that came on it but there hard as bricks