Last week, we told you about the importance of oiling piston valves. The same ideas hold true for rotary valves but the application is a little trickier. If you look at the picture at the top of the post it shows you what type of oil to put where but how do you do it? The bearing oil can be applied by removing the valve cap. The linkage oil can be applied by simply flipping the horn over. The hardest area to reach is unquestionably the most critical area to receive the oil, the bearing surfaces. To get oil on these surfaces, remove the slide tubes and drop the rotor oil down the tubes using a needle oiler. It is important to remember to use rotor oil not valve oil. The viscosity is not the same for these two different bearing surfaces and most not be confused.