TromboneChat

I have had issues with the second (D) valve on my Yam 620 bass for several years now. After having a repair person clean it, it will only be good for 2 or 3 weeks before it starts sticking again.

Over the last couple of years, the valve has been ‘re-set’ twice, ‘de-stressed’ and the horn thoroughly cleaned. It’s been seen by 4 different techs, all of whom are highly regarded. But, on each occasion, it came back working fine for about a couple of weeks, before getting sticky again.

It feels like a case of Yamaha’s tolerances being too fine. I had discussions with Yamaha in Toronto and they suggested I send it to a tech in Toronto look at it. He did some work on it, but now, a couple of weeks later, same story.

I use a Yamaha rotor oil and tried using it liberally and minimally, with the same result. Is there a particular oil that would work better than others?

Any thoughts or advice? (I’ve already considered ‘learn how to clean it yourself.’)

I borrowed a friend’s old Benge 290 for a while. I’d be surprised if anyone ever oiled the valves. They work great!

Sounds weird. I don't have any problems with my Yamaha valves hanging up. I hope someone will chime in. Probably very close tolerances like you said, or some kind of impact warping the casing, for instance.

Could you reach out to Yamaha Artist Services in New York? I think Wayne Tanabe still works there, and he may be able to shed some light on this issue. He is a well regarded tech, and may be able to tell you if this is something specific to Yamaha?

I’m in Canada and have been in touch with Yamaha Canada (who have been quite helpful).

If you just clean and relubricate the valve, does it reset the 2-3 week cycle?

Any signs of excessive gunk when you clean the valve? Wipe it with a clean, white (and expendable) cloth and see what you get.

And now, the total flyer...
Is it possible that the case is stressing the bell section?

The tech in Toronto raised the issue of the case stressing the valve and he said he de-stressed the valves.

Maybe I’ll just have to take it apart, clean it, and lube it regularly. I’m not very good at that sort of thing.

I would check the runout of the valve vs the shaft. Probably not very easy to do, you'd need a good setup and a good dial indicator. The shaft could be slightly bent, just enough so fresh oil makes it work but after a short time it binds.

You could have them use a super fine lapping compound and that should? make it better. If all they’re doing is cleaning this could be a solution.

Sounds like a warped valve casing to me

How subtle are these issues? I can’t imagine all four techs missing these.

Bach5G wrote: ↑Mon Nov 16, 2020 12:07 am How subtle are these issues? I can’t imagine all four techs missing these.

If it's a warped casing it can be pretty subtle. I have a horn with Olsen rotors and the first rotor has a warped casing. The F valve pretty much has the same symptoms as OP describes. Works great for a couple of weeks and then constantly binds. My tech is a world-class tech and it took them probably 4 trips before they realized it was tension and the casing was warped. With a tight tolerance valve, the warping can be microscopic and that's enough for the valves to bind.

OP do you hear the sound of brass rubbing on brass when you use the valve?

Bach5G wrote: ↑Sun Nov 15, 2020 9:48 pm The tech in Toronto raised the issue of the case stressing the valve and he said he de-stressed the valves.

Did he modify the case? If the problem is in the case, the permanent solution also lies in the case.

The problem is that, no matter whatever else the tech does to the valve in an attempt to fix the problem, he or she is going to also clean and relube the valve. Since a clean and relube seems to provide effective (albeit temporary) relief, it looks to the tech like the problem is fixed. It's only after you've played it for a couple weeks that the problem reappears. You need to find one tech who is willing to work with you on this, with the understanding that it's likely going to take multiple visits over a few months to get it sorted out.

What troubles me is that you played this horn for a few years before this problem manifested itself. If possible, you need to try to go back and figure out what changed at about the time you started having trouble. Did you change lubes (not just the valve lube, but the slide lube, too)? A new case? Did the horn have an accident?

...and yes, Yamaha is known for tight tolerances - but they were tighter when the valve was new than they are now, and it worked fine.

This was a used instrument in new condition. I noticed the valve issue immediately but the store assured me it could get the valve moving properly. And so it did. For a while. I didn’t play it much for several months when my bass trb playing opps dried up.

Since then I’ve had several techs work on it, as explained above.

Is the Herman’s #11 light rotor oil appropriate for close tolerances?

This might be a long shot, but...

Have you or any of the techs looked at tuning slide grease leaking down into the valves? Sometimes, if the tuning slide grease is too thin or if there is too much, it can run down into the valves, causing slowing and stickiness. If you use a lot of tuning slide grease on the F and Gb valve crooks, or if you oil the valves frequently, that will only make it worse.

Clean the horn thoroughly with something that will help cut the grease, or ask your tech to degrease the horn. Then find a thicker tuning slide grease (I use Ultra Pure thick, but others work well), and apply a small amount to the 1-2” of the ends of the inner tubing of F and Gb tuning slides. Work it in gently. If you have a hair dryer handy, gently warm the outer tubes of the F and Gb tuning slides prior to inserting the F and Gb crooks. You might need to apply some more, but in this case you might do better with too little tuning slide grease rather than too much.

It’s worth a try.

I also seem to remember here on TC (or perhaps the old TF) some people mentioning problems with Hetman’s lubricants. Sorry, I don’t remember what the problems were—I switched from Hetman’s to Ultra Pure a few years ago and haven’t tried any other lubes since then, other than Trombotine for the main slide.

I’ll search the Hetman issue. The horn was thoroughly cleaned as part of the most recent servicing.

You've disconnected the lever and spun the valve core by hand to make sure it isn't the mechanism binding, right?

I've had something like this happen to me on an older and looser tolerance valve. The slide is a long lever, and the wrong pressure on it can really tweak the valve/main brace area. That is the kind of thing that will warp the casing. Or like Doug said, you might have a bent shaft on the valve core. Tech might have to chase out the valve with a cutter to take out any low spots. Check the valve for leaks.

Once on a Kanstul, the backplate went sideways on it enough to make the valve stick. If the casing is warped, this could also happen more easily. If you have any facility with tools at all, you might try to remove the lever mechanism, loosen the valve cover, and then tap on the valve core shaft lightly (with wood/rawhide/plastic mallet) to slightly move the backplate without removing it, and see if that helps your problem. It might also misalign your valve a little, but that would help diagnose the problem (if it works, you have a wonky backplate, either not made right or fits into the valve casing crooked)

So yeah, warped casing or bent core shaft. Take it to someone who has already taken your money and have them take a closer look.

A few drops of the Yamaha rotor oil down the D slides helped last night but this morning the valve was sticky again. However, I found a bottle of Hetman 12 in my trombone cabinet and a couple of drops down each of the D slides restored a reasonable level of function.

Tech #4, the most recent, recommended the Hetman for its anti-oxidation properties.

Hmm, that is somewhat odd. I've got several Yamaha trombones, and haven't had any valve issues. Maybe something happened to it during shipping at some point?

Has it always been like this?

I explained above that it was used but in as new condition. I wonder if it was traded in because of the valve.

After several days of Hetmans each morning, the valve is playable. A testimonial to Hetmans, I suppose. Perhaps the long term solution is to get used to cleaning the valve regularly and frequent (daily) applications of Hetmans.

Bach5G wrote: ↑Thu Nov 19, 2020 4:17 pm After several days of Hetmans each morning, the valve is playable. A testimonial to Hetmans, I suppose. Perhaps the long term solution is to get used to cleaning the valve regularly and frequent (daily) applications of Hetmans.

Where are you located? If you are anywhere near Washington State, I would look up Oberloh Woodwind and Brass works. If they can't fix it no one can. I'm just amazed that a tech hasn't been able to give you a good answer yet. They have the tools to measure everything about the casing, and looking at the valve itself should show them exactly where it is sticking due to wear.

I’m just over the border, in BC. The border remains closed to non-essential travel.

The Hetmans seems to working though. I am using 12, which I found in my box of trombone stuff. I might head into town and pick up some 11 tomorrow. I am quite surprised at how effective the Hetmans 12 has been.

——

The 12 was good and a few drops of 11 this am was better yet.
__

The final update: it’s a miracle! The valve is as it should be. I’m very pleased (as long as I don’t think of how much I paid to techs when all I needed was a $9 bottle of rotor oil.)