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Yamaha Low Brass Valve Guide Maintenance

Yamaha piston instruments are equipped with plastic valve guides (metal valve guides - part #G0141090 were used previously).
The new guide material was recently changed to a harder plastic to resist wear. The part number for this newest plastic guide is #G0141092.
The following diagram shows the assembly procedure for the new plastic valve guides.



Make sure the guide pin on the bottom of the plastic guide fits into the smallest hole on the top of the piston. The other larger hole is an air vent.


Put a very small drop of Lock Tight on the threads (in the top of the piston) before installing the valve stem. This will help keep the stem from coming unscrewed causing the guide to come loose and spin around on the piston.
Just before tightening the stem, push the plastic guide with your thumb so that the guide tip sticks out over the piston as far as possible.
After oiling, place the piston very carefully back into the casing aligning the guide tip with the guide channel inside the casing. Make sure the piston is all the way in before screwing down the top valve cap.


We encourage you to pass this information on to band directors and there students in order to properly maintain there Yamaha instruments.


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