I am a newbie to this excellent website and forum. I have a Besson 1966 (purchase year) Model 181 silver 4-valve compensating euphonium with the originally supplied Besson 10 mouthpiece. It has never had valve guides. It has been largely unused since 1975, but I have begun practicing again. I have 2 questions.
1) In reviewing this site, Mr. Werden (“All About Valve Maintenance”) indicates that the vent hole at the top of the piston must be kept clear, and states that if the wrong pad is put on top of the piston, it might cover the hole. At the recommendation of a member of this site, whose advice and input is greatly appreciated, I purchased new valve stem felts (euphoniumstore.net) that are intended for this instrument. However, these felts do cover this hole, and my first question is if this is truly a problem, and if so, how would I recognize it, and then what can be done to remedy it?
2) There are a number of posts on this site discussing the value, installation, etc., of valve guides. As far as I can tell, my horn appears to be operating without issue, and as stated, has never had valve guides. Question 2 is if valve guides are necessary or helpful when all seems to operating correctly, assuming that I would even be able to recognize a problem if it were present, and what those problems might be? Thank you.