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Has a synthetic oil and petroleum based oil been mixed on this rotor?

Could be a problem. If so, just give the horn a good bath, using a degreaser. (Repairman secret: Dawn Dishsoap)
Could be a number of things without seeing it. Could have gotten dented somehow, or whatever...
who knows...maybe sing this...to the melody of William Tell Overture:
To the tech, to the tech, to the tech, tech tech...

Start by running some warm soapy water through the valve to flush out old dirt that may be inside - leave to dry, then re-oil. My experience is that is usually enough to stop sticking rotary valves.

Otherwise take to a repair man to be professionally checked out.

if that doesn't work, maybe put a little dish soap down the tube where you're running the water and then spray until you don't have any more soapy residue come out

Yep, give it a nice, warm bath. flush the soap off inside and out with warm clean water, and oil your valve as normal.

einahpets wrote:Hi my 5th valve is a little sticky. I oiled it but it still is sticky does anyone know anything I can do to make it move smoothly? Thank you.

Just so we all know, what model of horn is it?

Have you: 1) put sewing machine oil on the upper and lower rotor bearings, including filling up the little "well" in the bottom rotor cap; and 2) have you put 3-N-1 oil on the rest of the linkage?

I don't mean to completely disagree, but since rotors float on the rotor bearings, at least in theory, they are never supposed to come in contact with the rotor casings, only the bearing points. Now, gunk can and does occur, but with most rotors, all the advice in the above posts, including washing stuff down the tubes, are the last steps after trying these two points first.

As far as popping rotors, I'm sure bloke will agree that should be done every couple of years anyway as a matter of course to make sure there is no corrosion, and check alignment and if there is any physical damage binding the linkage or rotor casing from a hard knock. If the horn has not has a good "once-over" in several years, it would be a good idea to have that done anyway, even if you have to pay for it yourself. (From the OP's other threads and posts, I gather he is an underclassman at a university, using a university horn. If I am wrong, please correct me on this point.)

This is not my wisdom. I only got these points from Roger Lewis.

My own 186 was getting sticky, and I was just about to take it in, when I remembered I had not done #s 1 & 2 for awhile. Soaked the bearings and linkage good, let it set for a day, and all stickiness on all four rotors disappeared.

In my experience, whether with pistons, rotors or slides, stickiness is one thing; but "catching" is quite another. If the rotor just seems slow, or sluggish, or pushes down fine but doesn't want to return, it is most often what I have described above. But if the rotor seems to "catch" in a certain spot, both coming and going, or "hang," at a certain spot, then immediately, sung to the tune of William Tell Overture: "To the tech, to the tech, to the tech, tech, tech!"