King 4BF rotor arm clash

Post Reply
Ted
Posts: 63
Joined: Fri Mar 23, 2018 12:40 am

King 4BF rotor arm clash

Post by Ted »

Hi all,

Hope you can help me. My valve rotor arm clashes with the valve tubing:
Image

When I use the valve now there is a loud clacking sound, which is not ideal. I put a temporary piece of felt in between to stop it. When the hron is back from the tech, the arm is not hitting the vavle tubing, but in a month of playing the clash is back.

Now the valve lever has quite a large offset from the brace. Can I somehow alter the position of the lever so it's lower and doesn't hit the valve tubing?

Position when valve is pressed down:
Image
Position when valve is not used:
Image
ChadA
Posts: 150
Joined: Tue Dec 04, 2018 5:27 pm
Location: Dayton, OH
Contact:

Re: King 4BF rotor arm clash

Post by ChadA »

Ted,
It seems like the string is slipping over time. There should be a way to fix that pretty easily. Loosen, don't remove, the small screw on the stop arm (the screw on the metal arm that the string wraps around). Put one thumb on the stop arm to hold it in place and see if you can move the linkage away from what it's hitting (the string will move around the stop arm and screw as the linkage moves to the right position). Then tighten the screw back down.

The bigger question is why is the string slipping.
User avatar
BGuttman
Posts: 5965
Joined: Thu Mar 22, 2018 7:19 am
Location: Cow Hampshire

Re: King 4BF rotor arm clash

Post by BGuttman »

You can adjust the "rest" position of the lever by loosening the small screw on the rotor arm and shifting the string a bit. If you can't figure this out for yourself, it will take a Tech under a minute to make the adjustment.
Bruce Guttman
Merrimack Valley Philharmonic Orchestra
"Almost Professional"
Ted
Posts: 63
Joined: Fri Mar 23, 2018 12:40 am

Re: King 4BF rotor arm clash

Post by Ted »

Did it!

That was actually very easy to do when you try the right screw...

Thanks.
Crazy4Tbone86
Posts: 1364
Joined: Tue Jan 14, 2020 10:52 am

Re: King 4BF rotor arm clash

Post by Crazy4Tbone86 »

Easily adjusted by the screw on the stop arm (the part that is attached to the moving rotor). Just make sure you only loosen the screw the slightest bit and allow the string to slip and then adjust the resting location of the lever.

Be careful with the screws on that black plastic rod. Over the years, I have seen a lot of those break due to over tightening
Brian D. Hinkley - Player, Teacher, Technician and Trombone Enthusiast
Post Reply

Return to “Modification & Repair”