They're vacuum operated in the On and Res setting and fuel runs straight through it on pri. The pickup for the On is like 2 inches taller than the Res pickup - posted a picture around here someplace on the measurements.

reduildable? - maybe they can cause you a lot of grief if the diaphram leaks - if you run well on Res but not with On - I'd pull the petc0ck and have a look - you can remove the screen/filter/pickup tube - but be very careful as it can break rather easy

I did see one on ebay with some other parts recently for not much -

New they are like $45 from crotchrocket.com

There is a less expensive alternative to replacing the stock fuel valve with another stock valve. Non-vacuum valves are available from sources like Bikers Choice for under $15. Combined with a Pingle adapter plate you can have a valve with on-off-reserve for under $30 including shipping. Here is a link to the Yamaha 650 site that goes through installing a valve. Pingle makes an adapter plate that has pre-drilled bolt holes for different metric applications. If you want to keep the vacuum function you can buy Harley style valves that are vacuum operated.

http://www.650motorcycles.com/Petcock.html

If the link doesn't work (because of the word "petc0ck" try typing the following in your browser:

http://www.650motorcycles.com/Petcock.html and substitute the correct work for Petthingy.

I tried to edit it to allow a link to function and it worked on preview but not in actual use.  Bleh!

Rob (Savage_Rob)