Yamaha YFH-731 valve assembly

boppin' bob · New Member Joined: 05 Jan 2020 Posts: 4

Why do all 3 valves not seat in their valve casings? I am not able to screw down the valve cap - doesn't even get close enough to the threads. From the bottom up the valve looks like this: 1) the piston, 2)valve guide, 3)spring, 4)screw - on cap assembly. However,the nylon valve guide sits on top of the casing above the threads. Isn't it supposed to be inside the casing in the keyway? This set up prevents the valve from moving. Before I get too far along with the"senioritis" thing, would someone be able to solve this?

a.kemp · Posted: Tue Jan 21, 2020 5:39 pm Post subject:

They’re bottom sprung valves. The spring goes under the piston

jazzvuu · Posted: Tue Jan 21, 2020 6:30 pm Post subject:

There is a notch on the top of the valve that must line up with the value casing.

boppin' bob · New Member Joined: 05 Jan 2020 Posts: 4

[quote="jazzvuu"]There is a notch on the top of the valve that must line up with the value casing.[/quote] Thanks for your reply. I probably didn't accurately describe that the glide cannot be inserted into the casing even when the tab is lined up with the keyway. It sits on top of the casing threads because of a larger O.D. Any attempt to push it in results in a distortion of the glide . One member suggested that the valve spring is under the piston - not on top. However,The same problem with seating the glide remains. I'm sure there is a simple answer to this and I appreciate your time. I will gladly accept any further info.

LittleRusty · Posted: Tue Jan 21, 2020 7:42 pm Post subject:

Have the valves ever fit? Or did you purchase it with the pistons out of the casings?

When I purchased new valve guides for my Yamaha flugel they too were too long to git in the groove. A tech at the shop where I purchased modified them filed them to fit. I don’t believe this is the way the correct guides should work, but they have been fine since then.

Crazy Finn · Posted: Wed Jan 22, 2020 3:01 pm Post subject:

You made me dig get out my 731. Not a bad thing...

It should be in order from top to bottom:

- Bottom Valve Cap
- Valve Spring
- Valve (mine is grey colored)
- Metal Valve Guide (Nickel?) is attached almost at the top and this very top part of the valve is brass colored.
- A thin cork ring/gasket thing around the valve stem
- A felt ring above the cork ring and around the valve stem
- Vavle Top Cap
- Valve Button

There are Yamaha bottom sprung baritones that have plastic valve guides that attach to the top of the valve. That's not what I have on my 731.

I would take a picture but don't have a image hosting account, so no where to put it. I used to have ... something but it stopped functioning for linking to my posts - which is all I used it for.

I suspect that it's simply assembled incorrectly. Do you have a knowledgeable trumpet colleague with a Yamaha flugel or one that's familiar with a Yamaha flugel? Perhaps a local shop can assist you (I know mine would).
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