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Valve rotor skirt/web removal?
Posted: Thu Jan 25, 2018 6:52 pm
by bigtubby
A few years ago I remember a thread here about grinding away the skirt or web between ports on valve rotors but it seems to have disappeared.
Recently I acquired a Yamaha YCB-661 and one of its excellent playing characteristics is a very clean "finger slur". It either was built with this feature or someone has modified it.
Any input/opinions on this mod?
Re: Valve rotor skirt/web removal?
Posted: Thu Jan 25, 2018 11:40 pm
by Dan Schultz
bigtubby wrote:A few years ago I remember a thread here about grinding away the skirt or web between ports on valve rotors but it seems to have disappeared.
Recently I acquired a Yamaha YCB-661 and one of its excellent playing characteristics is a very clean "finger slur". It either was built with this feature or someone has modified it.
Any input/opinions on this mod?
A few years ago I experimented with removing material from rotor skirts to lessen friction and reduce weight. I thought I put them on my web pages but don't see them there now and cannot locate the images. I still have one of those rotors somewhere. I'll try to dig it out and send you some pics.
Re: Valve rotor skirt/web removal?
Posted: Fri Jan 26, 2018 1:03 pm
by bigtubby
Dan Schultz wrote:bigtubby wrote:A few years ago I remember a thread here about grinding away the skirt or web between ports on valve rotors but it seems to have disappeared.
Recently I acquired a Yamaha YCB-661 and one of its excellent playing characteristics is a very clean "finger slur". It either was built with this feature or someone has modified it.
Any input/opinions on this mod?
A few years ago I experimented with removing material from rotor skirts to lessen friction and reduce weight. I thought I put them on my web pages but don't see them there now and cannot locate the images. I still have one of those rotors somewhere. I'll try to dig it out and send you some pics.
Thank you Dan!
What I remember was a thread her on the forum discussing this as an improvement in air flow and cleaner transitions between valve positions. On closer inspection, the Yamaha's ports in the rotors don't go straight through, but are concave. A photo:
Re: Valve rotor skirt/web removal?
Posted: Fri Jan 26, 2018 11:35 pm
by Dan Schultz
bigtubby wrote:... What I remember was a thread here on the forum discussing this as an improvement in air flow and cleaner transitions between valve positions. On closer inspection, the Yamaha's ports in the rotors don't go straight through, but are concave. A photo:
AHA! This is something quite different from what I was doing. You might try searching for 'scooped' rotors.